A video shows clips of a few of Ben's aliens, such as Wildmutt, Swampfire, Brainstorm, Echo Echo, Jetray, Cannonbolt, Humungousaur, Rath, Big Chill, Chromastone, Goop, and Spidermonkey. The video finally shows the world about Ben's secret identity, with Kevin telling him that he's so busted Ben, Gwen and Kevin watching TV at home.
With Ben's identity revealed, the paparazzi made it hard for him to get out of his house, and TV reporter Will Harangue is criticizing him. While talking with Julie in the DX Mark 10, Kevin and Gwen show up telling Ben that they found out who revealed Ben's identity. But they find that Ben's so-called "Mastermind" is revealed to be a 10-year-old boy named Jimmy Jones.
Kevin gets mad for Jimmy ruining Ben's life, but Ben and Gwen forgive him. Jimmy tells Ben that he was looking at pictures of aliens around the world and noticed that most of them came from Bellwood and most of them were wearing the Omnitrix symbol and Jimmy was able to piece together Ben's identity from a picture of him wearing the Omnitrix. Jimmy wanted to just let the world know how cool Ben was, hoping he would like the fame and money. Gwen sees a picture of a red creature and Jimmy shows a video of it attacking two guards. Jimmy tells the team that all of the sightings are in Florida. This sounds like trouble for Ben and company, so they use Kevin's new jet (standard plumber issue) to travel to Florida. But then after an incident involving Kevin and the air force, Ben ends up in jail after saving an air force soldier as Jetray. He is able to be let out when Gwen and Kevin show the government their Plumber's Badges. They tell the team that the creature Jimmy showed them arises from the ocean to collect pieces from NASA's most powerful rocket ship. So Ben, Gwen and Kevin decide to stop this creature. But the creature seems too strong for both Gwen and Kevin and as for Ben, the Ultimatrix won't let him transform and begins acting weird.
Ben finally is able to transform after scanning the creature's DNA and transforms into Chromastone, his first reappearance after his "death", and fights the creature, but it proves too strong for Chromastone as well. It gets away and when Ben wakes up, the general tells Ben that the creature got away with the nuclear bomb, the engine for the rocket. Gwen gets the team underwater and finds the creature in a cave fixing his ship, wanting to go home. But the nuclear bomb will destroy all of central Florida, something the creature doesn't feel concerned about. To stop the team from keeping him from leaving, he throws a live cable at Gwen and Kevin, trapping them while Gwen is shielding them. Ben changes into Spidermonkey to fight, but the creature is too superior for all of Ben's forms. To take drastic measures, Ben changes into Ultimate Spidermonkey and easily defeats the creature, then traps it with Ultimate Spidermonkey's webbing. When Ben changes back the creature tells his name to be Bivalvan. He tells Ben that he, along with four others, were captured by a man called Aggregor and comes from the Andromeda Galaxy. He was able to escape him, but got separated and got stuck on Earth. So to help, Ben calls the Plumbers to help Bivalvan get home and stop the nuclear bomb from exploding.
The next day, when Ben goes to school, he's scared that his classmates will hate him too. But decides to go in after a kiss on the cheek from Julie, as encouragement. When Ben comes in, his classmates actually applaud him for his help, including his old bullies, Cash and J.T.. Later, Bivalvan is expecting the Plumbers, but instead Aggregor shows up and recaptures Bivalvan before torturing him. Bivalvan is also heard screaming off-screen.
Ben is fighting a Yeti that's being mind-controlled by Dr. Animo while Gwen and Kevin try to disable the device that Animo built that will turn people into Yetis. Ben is able to turn the Yeti against Animo using Brainstorm's electrical brain power and Kevin is able to disable the device.
Meanwhile, a turtle-like creature rampages and Ben, Gwen, and Kevin fight it. Realizing the creature doesn't talk(in English), they use their Plumbers badges as a universal translator. He reveals his name to be Galapagus and is looking for Ben for help. He's from a peaceful planet called Aldabra where he and his other friends ate grass all day and enjoying the great gift of life. Galapagus said his kind lacks aggression. It was normal until Aggregor showed up, killed, and absorbed one of his friend's powers, then later on, he was captured by an Osmosian(like Kevin) named Aggregor. His goal was to absorb Galapagus' powers along with four others from other species, such as Bivalvan (from Water Hazard's species), P'andor (from NRG's species), Andreas (from Armodrillo's species), and Ra'ad (from AmpFibian's species, The Amperi). These other aliens constantly call him names such as "turtleboy" and "amphibian face." The five aliens eventually decide to work together to free themselves from Aggregor.
They free themselves and get their powers back. P'andor and Andreas decide to take over the ship, but Bivalvan, Ra'ad and Galapagus decide to call for help. Magister Prior Gilhil responds to the message and the aliens are taken back to their prison, but Gilhil is unfortunately attacked by Aggregor. It's confirmed by Dwayne McDuffie that he was killed on the spot.
When the aliens escape again, Galapagus has neutralized their powers and gives them to Aggregor in exchange for freedom, but he double-crosses Aggregor and neutralizes him and leads the aliens to an escape-pod. They crash-land on Earth in Florida and decide to separate to look for help while Bivalvan repairs the ship. Before Ben contacts the Plumbers, the Ultimatrix scans Galapagus' DNA for Ben. They then give Galapagus a ride home, but the Plumber riding the ship is revealed to be Aggregor in disguise and recaptures Galapagus to absorb his powers.
A strange alien is offering big money (probably $1 million) to someone who can open a safe (which is really a containment suit). That alien is revealed to be P'andor who wants to be free of his containment suit. Surgeon, Buzz and Hammer tried to break open the armor but all had failed. After a while,Kevin who heard about it tries to free P'andor by absorbing a Taydenite sample he kept and using it to open the armor, but then changes his mind when his Plumber's Badge detects a high level of radiation. Kevin then fights off P'andor and his minions, promising them $100,000 if they can capture him. Kevin then goes into his car and escapes, leaving behind his Taydenite sample. Later Ben and Gwen talk about how they looked for the aliens who escaped Aggregor and following Jimmy Jones' tips. When Kevin arrives, Gwen makes the boys go back so they can help P'andor get back to his home like Bivalvan and Galapagus (unknown that they were both recaptured by Aggregor). They track P'andor and his minions to a flint-mine, where they take one of the drills and use the piece of Taydenite Kevin accidentally left behind to free P'andor. Ben tries to stop them as Humungousaur. But when P'andor and his minions threaten to hurt Gwen and Kevin, Ben turns into Ultimate Humungousaur to fight them off so they don't hurt Gwen and Kevin. But Ultimate Humungousaur's missiles begin to make the flint-mine crumble down.
Ben tries to keep the flint-mine from crumbling down and Gwen and Kevin have an argument about whether brain or brawn is better while P'andor and his goons escape. Kevin uses his powers to keep the flint-mine from coming down and leaves. P'andor then attempts to use a Taydenite on a drill to break the armor but it still failed(even breaking the drill)and realizes that the only way to escape from his suit is by needing Kevin to absorb the Taydenite. He has his goons attack Kevin and kidnap him. Then they all taunt him causing him to lose his temper and absorbing the Taydenite; unfortunately, he slashes at P'andor's suit, which gives him freedom.
P'andor begins to absorb energy and fires at his goons when they ask for their prize money. Ben and Gwen show up and find Kevin, who's shameful for what he's done. Ben then tries to go alien, but the Ultimatrix goes into capture mode and absorbs P'andor's DNA while Gwen tries to make peace with the highly radioactive alien, but he mistakes Ben absorbing his DNA for a weapon and attacks her. Ben is then able to save Gwen and lands her at front of Kevin who tells her to be more careful later. Jetray fights off P'andor but he can't touch P'andor and his blasts will only feed him. P'andor then spots a power plant and tries to absorb the energy. In order to get P'andor to leave, Ben changes into Water Hazard and pretends to be Bivalvan and pretends to be his friend in order to convince P'andor to leave Earth. But unfortunately, the plan fails and Ben attempts to use Water Hazard's powers to stop him, but it also failed. Ben tries to stop P'andor as Big Chill so that he can match P'andor's fire powers with Big Chill's ice and that they can't touch each other.P'andor successfully absorbs the energy and becomes a giant. Kevin and Big Chill both design a plan to get P'andor back into his suit, so Kevin absorbs a material that can absorb the extra uranium inside P'andor. Then Ben turns into Cannonbolt but realizes it's not enough so he manages to get Kevin to put P'andor's suit back on by using Ultimate Cannonbolt to trap him. Kevin also makes an improvement to his suit by welding the wrists together behind P'andor's back to keep him in place. Ben and his friends get two Plumbers to take P'andor back to his home world and now have to focus on finding Andreas and Ra'ad, but the Plumbers are attacked by Aggregor's spaceship and P'andor is recaptured by Aggregor just like Bivalvan and Galapagus.
Local alien con artist, Argit is going to Forever Knights' castles offering "insurance", but when they refuse, the castle crumbles down to nothing and Argit leaves.
Meanwhile, at Mr. Smoothy, Ben is celebrating his hero status and Ben 10 fans (or as he calls "Benatics") come to meet their favorite hero and get autographs from him with cups of his various aliens. But suddenly, the Forever Knights crash in and take one of the smoothy machines. Ben tries to stop them as Spidermonkey, but his big ego and fans block him from doing so. Ben, Gwen, and Kevin go to Jimmy Jones for help and reveals that the Forever Knights have also stolen pizzas and burritos, but they didn't steal any money from the places they stole the food from. They go to a Forever Knights castle (one of the knights are friends with Jimmy and he was in that particular castle when the castle was falling apart in the background) to investigate, but finds it destroyed.
They sneak into another castle in Ben's car (much to Kevin's annoyance, as he was in the back seat) using Jetray and find that Argit is being leader of the Forever Knights there and steals junk food just to amuse him. If the castles he goes to refuse to let him rule their castles, he will use his new friend Andreas to destroy the castle. Andreas is also one of Aggregor's victims. Ben then scans Andreas's DNA and gains a new form. He gives Kevin money as payment for the money he owes him. Kevin then says that he loves money more than anything else in the world, and Gwen gets mad at him for the remainder of the episode. Argit tells Andreas that Ben and his team are friends, but then a Forever Knight intelligence officer named Sir Dagonet comes in and turns Argit's Forever Knight garrison against Ben and his friends.
He puts Argit and the others into a dungeon after Argit cowardly tries to save himself by telling Dagonet that Ben and team were forcing him to pretend to be the leader of the Forever Knights. However, Andreas is to be executed by Dagonet and his death squad for being an alien. Argit convinces Ben and his friends to break him out in order to save Andreas. Ben uses Goop to free himself and his friends, then goes to save Andreas. Ben fights the Forever Knights as Swampfire while Argit and the others save Andreas. But Dagonet turns the weapon he was using to kill Andreas into a self-destruct bomb to kill Ben and the others. Argit convinces Andreas to absorb the quake of the bomb and leave, thinking Andreas sacrificed his life to save his friends. They leave but then Aggregor shows up and finds Andreas badly injured. He heals him and takes him to his ship, then puts him in a stasis pod next to Bivalvan, Galapagus, and P'andor. Now all that's left is Ra'ad and then he says, "the fun can begin".
After Kevin and Gwen drop Ben off at his house, Ben can't get rid of the feeling that something is following him. While sleeping, lightning goes through the electrical lines of Ben's house and then suddenly, Ra'ad, the last of Aggregor's prisoners, shows up and attacks him. He changes into Jetray to fight him. The battle ends when Ra'ad falls into a pool while charged up and shorts out. Ben, Gwen, and Kevin then take Ra'ad to Los Soledad where they have him in a containment cell. Ra'ad tells Ben that it's his fault that Aggregor recaptured his friends (the other four prisoners). Ra'ad confirms that Aggregor is indeed an Osmosian like Kevin, and tells the trio that with the combined powers of himself, Bivalvan, Galapagus, P'andor, and Andreas, Aggregor would be the strongest and most powerful being in the galaxy. Ben offers to have Ra'ad work together with them to stop Aggregor. The Amperi seems to agree with the deal, but the moment that Ben releases him, he attacks the trio, having read Kevin's mind that if things got worse, he would hand Ra'ad over to Aggregor. At that moment, the Ultimatrix detects that Ra'ad's DNA is uncatalogued. Ra'ad states that Aggregor used Ben's Ultimatrix as a homing device to track the aliens and bypassed his calls to the Plumbers. To prevent Aggregor from finding him, he tries to destroy the Ultimatrix with a lightning blast, but it launches its scanning wave at the same time. The mixing energies cause an explosion which blasts Ben into the wall and damages the Ultimatrix while Ra'ad has mysteriously disappeared. As Ben laments that things can't get worse, Aggregor shows up to recapture Ra'ad.
Ben and his team try to fight Aggregor, but he proves to be too strong for them. The Ultimatrix finally lets Ben access a form, but unfortunately, all that he can transform into is Ra'ad. With no choice, Ben turns into AmpFibian and fights Aggregor. Unfortunately, he's still too powerful and decides to use Ben in his Amperi form as Ra'ad's replacement. Gwen then casts an unusually strong and unnamed teleportation spell to transport herself, Ben, and Kevin away from Aggregor to Kevin's warehouse. As Gwen recovers from her teleportation spell, Kevin has revealed he rebuilt the machine they had used to try to hack the Omnitrix during Vengeance of Vilgax on Alien Force to reboot the Ultimatrix and change Ben back to normal, since he's stuck in the AmpFibian form, although Gwen and Ben protest the idea. Suddenly, Ben begins hearing Ra'ad's voice inside his head and begins acting like him. It turns out that the blast accidentally trapped Ra'ad inside the Ultimatrix. He refuses to allow the Ultimatrix to be reactivated because Aggregor would find them. At the same time, he's slowly taking over Ben's body.
While Gwen holds AmpFibian/Ra'ad inside a magenta-purple electric glowing energy sphere, Kevin absorbs a rubber tire to enable him to get near AmpFibian and use jumper cables attached to the machine to reboot the Ultimatrix. This time, the experiment is a success. Ben and Ra'ad are separated and Kevin remains unmutated. Unfortunately, with the Ultimatrix's signal restored, Aggregor is free to find them. Rejecting Ben's offer to fight together, Ra'ad quickly escapes as Aggregor crashes in through the roof. After dispatching Kevin and Gwen, Aggregor demands Ra'ad from Ben, who tries to fight him using Brainstorm, but Aggregor's weapon easily defeats him since it's used to handle all electrical aliens. Aggregor then tries to forcibly change him back into AmpFibian by using his weapon on the Ultimatrix faceplate which nearly kills Ben in the process. Outside, Kevin(who was thrown there by Aggregor) sees Ra'ad and yells at him about letting the only person who wanted to help him die. Ra'ad attacks Aggregor and saves Ben. Ra'ad tells Gwen and a severely injured and weakened Ben to get out while he clashes with Aggregor. In the midst of the battle, Kevin's warehouse explodes for the second time, but Ben, Gwen, and Kevin manage to escape while Aggregor takes Ra'ad back to his ship in the middle of the blast. Now that Aggregor has all five of his prisoners, he's now able to resume transporting them to his home planet and carry out his plan of permanently absorbing all of their powers and abilities and make himself invincible. Kevin and Gwen believe it's all over, but Ben tells them that he vows to use the powers of his 5 new aliens to save the prisoners and stop Aggregor once and for all.
In a desert, Aggregor has Ra'ad in his capture. This takes place after Fused. Aggregor takes Ra'ad to his ship, but Plumbers arrive to capture him. Aggregor uses his ship's lasers to drive away the Plumbers and gets away with Ra'ad. He puts Ra'ad in a cage like the other captured aliens and attempts to escape, but the Plumbers attack his ship, destroying his hyperdrive.
Ben, Gwen, and Kevin are at Mr. Smoothy testing out what looks like a new smoothie flavor (lamb-and-sardine), which Ben seems to like. However, their hanging around is over when Ben's fans comes to harass him. Ben becomes Big Chill and then changes into Ultimate Big Chill and blocks away the fans. They see a Grandpa Max hologram on the Ultimatrix and go to the desert where Aggregor and the Plumbers fought. Kevin seems to know a lot about the battle's crime scene, which shocks the others. They take Kevin's jet to find Aggregor's ship. Gwen and Kevin talk, with Kevin shutting Gwen up with a kiss on the cheek. They find Aggrebots and fight them. Ben changes into Lodestar during the battle and they defeat the drones, so Ben decides to use Lodestar's magnetic abilities to stop the ship, but it explodes,
Gwen managed to protect Kevin and Max from the explosion and thought that Ben was killed, but Ben recreates himself back into Lodestar. They wonder where Aggregor is, and they find out that he is at the Los Soledad military base. They find Paradox's time-travel machine, which he is going to use to absorb the other aliens' powers. They talk to the Military Colonel Rozum and Paradox arrives, where he explains Aggregor's use of his time machine. Colonel Rozum gives them permission to stop Aggregor, and Paradox leaves. The base is guarded with Aggregor's drones, so they battle, with Ben becoming Swampfire (changing into Ultimate Swampfire immediately after). Aggregor releases Bivalvan, Galapagus, P'Andor, Andreas, and Ra'ad, but takes control of their minds and has them attack Ben and his friends.
A fight is engaged against the team and the other aliens. They release Bivalvan from control, but he disappears. When Ra'ad squeezes Ultimate Swampfire, Ben becomes Nanomech and shoots Ra'ad's head piece, and he disappears too. The same happens to the others. Aggregor then begins to absorb energy and Kevin tries to reason, explaining that regularly absorbing energy caused him to go insane when he was a kid (in the original Ben 10 series when he was Kevin 11 ), but Aggregor doesn't listen, claiming that it is a lie used to control the weak. Before Kevin can further reason with him, Aggregor shoots Kevin with his spear . He then powers himself and breaks the fabric of time. Ben becomes Humungousaur and destroys the machine, but Aggregor escapes and the aliens disappear. Aggregor reemerges as being fused with all of the aliens, and has become Ultimate Aggregor.
From the previous episode, Aggregor has absorbed the powers of Bivalvan, Galapagus, P'andor, Andreas, and Ra'ad, transforming him into Ultimate Aggregor. Ben Tennyson, as Humungousaur, battles Aggregor in a fit of rage and anger. As Ben was about to beat Aggregor some more, Gwen stops him with her force-fields. However, the attacks did nothing to Aggregor, as now he has Bivalvan's invulnerability. He's now also immune to Gwen's mana attacks, which is from Galapagus. He then battles Kevin and Gwen and defeats them. Ben tries to attack him again, but Aggregor defeats him with one, earth-shattering punch, and then leaves. Ben wakes up from Aggregor's attack to see Azmuth in his face. Azmuth seems disappointed by the Ultimatrix's workmanship and its evolutionary begging for trouble, which was made from his former assistant, Albedo. Azmuth then tells that Aggregor is now looking for the most important object in the universe.
Azmuth brings Ben, Gwen, and Kevin to Galvan Mark II, where he explains that the reason Aggregor absorbed the powers of the aliens was to become unstoppable on his quest to collect the pieces of the Map of Infinity, which can give the user its power to travel anywhere in seventeen dimensions. Aggregor wants the Map to reach the Forge of Creation, and become even more powerful. To make sure the map's power doesn't fall into anyone's evil hands, Paradox divided the map into four pieces, and placed them in random places. The group's job is to collect the pieces before Aggregor can obtain them. Grandpa Max is forced to stay off the mission as one of Aggregor's attacks damaged his whole nervous system, and is supposed to be giving him a new one. Ben, Gwen, and Kevin go to the place where the first map piece is held, a half-fire, half-ice planet. The team has to wear Plumber suits or they could die in the planet's atmosphere. They find the temple where the map piece is held, but it's guarded by white Necrofriggians (Big Chill's species). Gwen tries to make peace with them, but after Ben (as Big Chill) mentions taking an artifact, they attack Ben is to stay as Big Chill, because the transformation destroyed his Plumber suit. When Big Chill proves to be too weak, Ben becomes Echo Echo, but later becomes Ultimate Echo Echo. They manage to get in the temple and the Necrofriggians leave them, but their leader says they won't be able to pass the following traps without a guide. Kevin accidentally springs a trap and a giant spiked hammer comes and seemingly crushes them.Gwen was able to protect them with her powers and now Kevin's suit is torn, too, but he's able to survive when he absorbed the stone on the hammer. Gwen springs another trap, and she and Kevin fall into a vat of boiling acid, but Ben manages to save them. They then fight a two-headed monster, and after defeating it with Ultimate Echo Echo's sonic discs, they go on ahead. Ben once again springs another trap and they run through a corridor of poisoned darts. They reach the door containing the map piece in it, and Ben as Four Arms and Kevin lift the door for Gwen to go inside and collect the piece. However, she learns she's struck by a poison dart and passes out. Aggregor comes and reveals he made Ben and his friends go through the traps for him so he wouldn't have to do it himself. Aggregor takes the map piece and leaves. While Ben holds the door, Kevin picks up Gwen and they escape the temple by Ben crashing through as Cannonbolt. But once they reach the ship, Ben changes back to his human form and passes out. Kevin is able to get Ben and Gwen in the ship and takes off. Kevin heals Gwen from her poisoned dart, and Ben survives but now he has half of a sunburn on his face. As Kevin and Gwen thought it was over, Ben says he will make Aggregor pay and promises to get one one of the last three Map pieces left before he does.
Underwater, a Magister Plumber named Pyke (Ripjaws' species) is searching for something. He finds a swimming object which happens to be Ultimate Aggregor who seems to have defeated Pike. Ben is being surrounded by fans and tries to escape as Goop, but Gwen and Kevin pick him up and save him. Ben receives a message from Pyke on his Ultimatrix about Ultimate Aggregor. They take Kevin's jet to go to Piscciss (Ripjaws' homeworld) to search for Pyke, but are attacked by a monster. They use the electrical gauntlets in their Plumber suits to defeat the monster, but in the battle Kevin's helmet cracks. With Kevin dying, Gwen gets him absorbing his jet's coating, while a nearby fish is able to convert itself into a helmet for him. Pyke shows up and the kids go with him to find Ultimate Aggregor. Ben's helmet cracks when they battle many sea creatures, and he tries to transform into an underwater alien to stay alive, but becomes Humungousaur instead. With a few moments to live, Ben becomes AmpFibian. They pass the guards once they explain their Plumber business, and go to the core of the planet, where it looks like Ultimate Aggregor is attacking. The core is able to have air in it, and Pyke uses a water helmet to breathe. But a tremor occurs and Pyke is crushed by a rock. While Gwen stays to help him, Ben and Kevin go on, but find Ultimate Aggregor grabbing the planet's core piece that keeps it together. It turns out the core piece is the second piece of the Map of Infinity, which Paradox did to cleverly disguise it so Aggregor would not suspect. Ultimate Aggregor leaves the core. Ben becomes Big Chill and chases Ultimate Aggregor. Gwen, Kevin, and Pyke have to deal with the core guards. Ben becomes Ultimate Big Chill when the guards keep confusing Ben and his friends as the culprits for stealing the core piece. Ultimate Aggregor, unfortunately, escapes with the piece. Ben, trying to prevent the planet from scattering into pieces, transforms into Goop again, and uses his antigravity device as a substitute, but it also sucks in Goop's body. Soon the planet's surface glows green (Goop's color) and the planet pulls itself back together, with Ben transforming back to himself and being saved by his friends before he drowns. Pyke thanks the kids for their help and Kevin wards off the fish that was used as his breathing helmet earlier (who grew a soft spot for him). They leave and now there are only two pieces of the Map of Infinity Ultimate Aggregor has yet to claim.
The group is chasing Aggregor, who happens upon a door and shouts an incantation, where the door glows symbols and opens to a world that looks like it is full of mana. Unfortunately, Ben as Four Arms wasn't strong enough to keep the door open and it closes. Ben remembers the glowing symbols and writes them down, but Gwen cannot spell out what the symbols read. She does know someone who can read the symbols, and ironically, that person is Charmcaster.
Charmcaster begins fighting Gwen before she could tell why she came, and Charmcaster stops fighting when Gwen mentions Aggregor crossing a portal looking to be made of pure mana. Charmcaster decides to help and she and Gwen go back to the door and Charmcaster says the incantation (Yawa Tobsic) which is the gateway to Ledgerdomain, the dimension making up of everything that is mana. Charmcaster explains she was born here, and that she and Hex were sent to Earth by Charmcaster's father, who was fighting the ruler of Ledgerdomain, Adwaita, but died in battle. Gwen also notices that her magical and Anodite powers and abilities have gotten much stronger and more powerful. Adwaita's stone creatures attack the group, and battle them. Ben tries to fight as Jetray, but flies like crazy since the sky and earth are not equal. Ben becomes Cannonbolt and the stone creatures are defeated, but are encountered by Adwaita.
Adwaita tries to kill the group by covering them with rock, but Charmcaster frees them and they flee from Adwaita. They are then attacked by Adwaita's stone bat-like creatures, and Ben becomes Chromastone and they fight the creatures while Charmcaster prepares a spell that will protect them. The spell works, and the creatures leave. Soon, they come across a gap, where Charmcaster hears her father's voice, telling her to step into the gap to reunite with him. Gwen is able to convince Charmcaster it is a trick, and they move on. Soon, they are encountered by Adwaita's guard, Palorfang. Ben becomes Humungousaur and fights the creature, where he kills it by pushing it off a cliff. Adwaita, angered by Ben killing his creature, attacks them and entraps them in frozen blocks. Ben becomes Ultimate Humungousaur and frees the others and fights Adwaita. The Alpha Rune, the key to all of his magical power and strength, is gone and he is attacked by Aggregor, where the Alpha Rune is revealed to be a piece of the Map of Infinity. Aggregor escapes the crashing dimension, and Charmcaster helps the team get out, but stays behind to free her people, and they promise to come back and help her. Now Aggregor has nearly all the pieces of the Map of Infinity, and the team vows to make sure Aggregor will pay, and find some way return to help Charmcaster and free her people.
Azmuth contacts Ben on the Ultimatrix, and not happy at him for failing to stop Aggregor from claiming three of the four pieces to the Map of Infinity. Ben tells Azmuth that scolded at him is not going to help him, Azmuth agrees then teleports Ben, Gwen, and Kevin to another galaxy to the Perplexahedron, a giant cube-like artificial planet, and find Aggregor approaching the planet.
The group chases Aggregor, but he is able to successfully get in using his three pieces of the Map of Infinity, and the group is able to get in there as well, but barely. Gwen cannot track Aggregor, and they end up going through random doors that seem to defy gravity. Ben gets Gwen to make trackers on the floor, and it shows the hallways are moving down to random rooms. When Kevin punches the locked door, it activates its security system. Ben tries to become Chromastone, but instead becomes Humungousaur. And now, they are waiting their supposed death as the lasers move in closer to them.
Gwen manages to destroy the lasers, but then they encounter a big, white humanoid robot, which they later defeat. They encounter another trap, which is a wind tunnel, and Ben and Kevin and Gwen are separated. Gwen fights more security drones and encounters Aggregor (who simply ignores Gwen). When the room Ben and Kevin are in is flooding, Ben becomes Ripjaws to free them. The next room they go in becomes filled with acid, and Ben manages to save him and Kevin using Spidermonkey. Gwen and Aggregor keep going through the Perplexahedron, where they keep encountering security, but Aggregor easily destroys the traps. Soon, they come into a room where it is snowing, and Aggregor finally gets tired of Gwen when she tries to get his attention, so he hoses her into a wall, where she becomes a frozen statue.
Ben manages to free Gwen from her frozen prison as Swampfire, and she and Kevin kiss. They realize to get to the final piece of the Map of Infinity, they have to go through the rooms where the guards appear. They do that, and soon encounter the Sentinel, the keeper of the final piece of the Map of Infinity, and his crown is revealed to be a piece of the Map of Infinity and knows a lot of Aggregor's plan. He tells Ben that his mission in protecting the final piece has succeeded and that the Perplexahedron has fulfilled its purpose. The Perplexahedron begins to crumble and Aggregor appears and beats the Sentinel for the Map of Infinity. Ben becomes Cannonbolt and Aggregor is able to defeat him, but Ben becomes Ultimate Cannonbolt and begins to deathly hurt Aggregor for his crimes. But Aggregor is still unbeatable, and fights off Ben, then takes the last piece of the Map of Infinity. Ben, Gwen, and the Sentinel are picked up by Kevin, and the Sentinel yells at Ben for his failure to not protect the Map of Infinity, where he blames Ben for losing the piece and then disappears. But the team still vows to stop Aggregor once and for all, before he puts his plan into motion.
With Aggregor having all four pieces of the Map of Infinity, it looks like his plan will come to fruition. An upset Azmuth scowls Ben, Gwen, and Kevin for failing to stop Aggregor. As Azmuth believes all hope is lost, Ben says there is still another way to stop Aggregor. He says Kevin put in a security system to prevent the transformation of Alien X, so Gwen and Kevin give Ben their keys and unlock Alien X, then Ben transforms into him.
Inside Alien X, Ben tries to get the attention of Serena and Bellicus. As they begin arguing over minor things, Paradox suddenly appears, causing the two personalities to grow upset and attempt to destroy Paradox, as he is prohibited to be within 500 light-years of them, until Paradox is able to turn Ben back to normal and out of Alien X. After some arguing between each other, Azmuth and Paradox explain that Aggregor's plan is to use the Map of Infinity to enter the Forge of Creation, where Celestialsapiens (Alien X's race), are born. Aggregor is intent on absorbing the powers of a newborn Celestialsapien that has not developed the personalities of Serena or Bellicus, and can easily conquer the universe. Paradox brings Ben, Gwen, and Kevin to the entrance to the Forge of Creation, where he leaves them as he cannot go there. Soon, the group is attacked by Aggregor's drones, and Ben is able to get rid of them using Terraspin. Unfortunately, Kevin's jet hits a wedge in the time barrier, and Ben accidentally falls in, only to be saved by Gwen. But Ben just realizes he has brought his ten-year-old self with him.
Young Ben notices Kevin, and still believes him to be evil. He transforms into Heatblast and fights Kevin. Ben tries to become Big Chill to stop Young Ben, but becomes NRG instead. Soon, they reason with Young Ben, explaining Ben is his older self and that Kevin is no longer evil. Young Ben notices Gwen, and instantly insults her like in the original series. With no way to get Young Ben back to his own time, he is forced to join the others. Along the way, Young Ben admits why he was so obnoxious six years ago and looking through the Ultimatrix, seeing how "lame" the aliens except Humungousaur are. They reach the Forge of Creation, filled with giant Celestialsapiens, frozen while debating. They come across against an even bigger female Celestialsapien, holding the baby Celestialsapien in her hands. But then, Kevin's jet crashes, and they crash into the mother Celestialsapien's palm.
Both Bens become Four Arms (though they were aiming to go Upgrade and Big Chill). Aggregor suddenly approaches them and easily defeats them like before. Ben turns Young Ben into Stinkfly to distract Aggregor, while Ben becomes Swampfire, then Ultimate Swampfire to fight Aggregor. But Aggregor is still too powerful, and still defeats both Bens. Young Ben says that Kevin could absorb the aliens on his Omnitrix like before, but Kevin instead chooses to absorb Ben's Ultimatrix, and becomes a combination of Diamondhead, Brainstorm, Lodestar, Chromastone, Jetray,Swampfire, Big Chill, Humungousaur, Four Arms, Spidermonkey, and Rath. He prevents Aggregor from absorbing the baby Celestialsapien's powers, and absorbs his powers, turning Aggregor back to normal. Ben, Gwen, and Young Ben prevent Kevin from finishing off Aggregor, but by absorbing the energy of the Ultimatrix aliens, he has become insane once more. He even begins thinking of absorbing the baby Celestialsapien himself, but Young Ben complains Kevin is a jerk and is too busy feeling sorry for himself that he does not notice people try to be nice to him. Kevin leaves them, promising to "come back". Paradox appears, telling them he is sending Young Ben back home, and will think the whole adventure was a dream. Gwen tells Young Ben to be really nice to Young Gwen and kisses him, much to Young Ben's embarrassment. Paradox leaves with Young Ben, and now Ben and Gwen's current mission is to return Kevin back to normal.
Why He Needed Their Powers
- Ra'ad - Breathe underwater for Piscciss and for flight.
- Galapagus - Mana immunity for Ledgerdomain and flight.
- Andreas - To move through the Piscciss core.
- Bivalvan - Invulnerability and breathe underwater.
- P'andor - Temperature Resistance and energy beams.
- All Aliens - To survive the traps of the temple of Mykdl'dy, the Perplexahedron and the Forge of Creation and travel through space.