Gwen is now sixteen years old. Her wardrobe has altered once again, wearing a combination of her outfits from Alien Force. She wears her old outfit from the first two seasons of Alien Force, but instead of a plain dark blue shirt it is now dark red and she also keeps her high ponytail from the third season.
In Hit 'Em Where They Live, Zombozo and other villains teamed up to take revenge on the Tennysons and company, and kidnapped Ben's mom Sandra. Enraged, Gwen released her dormant, inner Anodite for the second time since War of the Worlds: Part 2. Whilst Zombozo trembled with fear, Gwen began to grow to a huge height, promising that if one of his teammates (and other notable villains) even bumps into their families on the street, she would come for them. Petrified, Zombozo screamed off-screen and Gwen saved Sandra. When Kevin asked what happened to Zombozo she simply replied "We came to an understanding" whilst smiling.
In Video Games, she tries out for her driver's license, earning it in the end.
In the episode Hero Time, it is shown that Gwen gets very jealous when Jennifer Nocturne starts flirting with Kevin after he saved her life. Kevin also protected Jennifer a lot, over the course of the episode.
During her attempt to recover the first part of the Map of Infinity, she discovers it was hit by a poison dart and ends up fainting, causing Aggregor to catch the first fragment, but Kevin and Ben save her from near death.
In Reflected Glory, Gwen is comprehensive with J.T. and Cash. In the final part of the episode, Gwen is seen with her shirt torn and her hair disheveled, after she and Kevin face the RED's again. Gwen had the idea to use a mirror against RED's, and her powers apparently did not greatly affect the RED's.
In Deep, the group goes to the planet Piscciss to help Magister Pyke stop Aggregor. Gwen is caught by a squid-like creature, but Kevin revealed that he installed neuro-shock pulsers which can shoot lightning, allowing Gwen to get free. When they reach the nucleus of the planet Piscciss, an earthquake occurs. Gwen put an energy shield around them, but failed to protect Magister Pyke, so she stays with him while Kevin and Ben go after the second part of the Map of Infinity. However, Aggregor arrived first and fled with the second part of the Map of Infinity after defeating Ben and Kevin. When the planet begins to crumble, Ben as Goop saves the planet, re-constructing the lost water particles using Goop's artificial gravity immobilizer. When Ben apparently dies, Gwen is devastated, but when she sees that he survived, she feels immediate relief. At the end of the episode, Gwen consoles Kevin for having to leave the Blowfish in Piscciss.
In Where the Magic Happens, Gwen relies on Charmcaster to help her, Ben and Kevin survive traveling through Ledgerdomain to find the next piece of the Map of Infinity, the Alpha Rune. Along the way, she learns of Charmcaster's sad background and comes to sympathize with her nemesis.
In The Forge of Creation, Gwen travels with Ben and Kevin to stop Aggregor from absorbing a newborn Celestialsapien's powers. Young Ben comes along as Ben accidentally falls in the time barrier. Gwen, Kevin, and even Ben became annoyed with young Ben. However everyone eventually understands why Young Ben is so arrogant and cocky, when dealing with the pressure and the danger that could kill somebody, Gwen's first-cousin tends to joke around so he can be prepared to face anything. Unfortunately, everyone was easily defeated by Aggregor, who seems to have won, but Kevin absorbed the immense energy of the Ultimatrix as a last resort, defeating him but becomes insane in the process.
In ...Nor Iron Bars a Cage, Gwen and Ben travel to Incarcecon to warn the warden about Kevin. The warden would have been killed if it were not for Gwen, (who saved him from crash landing using a much stronger version of the "Tur-bo" spell.) Ben implies Kevin needs to be "put down", which shocks Gwen.
In The Enemy of My Enemy, Ben and Gwen are shown to be having difficulties. The two argue about Kevin while trying to locate a ship. On the way, they stumble upon Argit, who needed a place to hide from Kevin. They travel to the Plumber's Academy in the Rust Bucket 3, only to be attacked by Kevin. They barely succeeded in defeating him, and Gwen said she turned the air lock on to send Kevin falling because she understood he would kill them if he had the chance. After Argit preformed his orders, Kevin attacks the Plumber's Academy. Ben uses Ultimate Echo Echo to deal with the nuclear bomb, while Kevin relentlessly attacked Argit. Gwen tells him to stop and to give himself up, but he knocks her down. Gwen remains there crying as Kevin spares her from his fatal blow, stating that she was only spared because of what she used to mean to him. Ben returns and the two have a conversation, Gwen says that they could still help Kevin, Ben replies that they cannot.
In Absolute Power, Gwen is more determined than ever to save Kevin. Ben disagrees with Gwen, opting to kill him now rather than a last resort. Gwen goes to Max, hoping he will disagree about killing Kevin, but her grandfather confirms that killing Kevin is the right decision. He also told Gwen that if she disagrees, she should leave Ben to do it and not get in the way. Gwen leaves, disappointed and angry, ready to take desperate measures as she goes to Michael Morningstar for help. Meanwhile, Ben goes off looking for Kevin, who's relentlessly going after anyone he thinks has betrayed him. Just as Kevin beats up Vulkanus, and begins to go after Ben, Gwen stops him, accompanied by Michael. Ben is infuriated by Gwen's alliance, but she makes a deal with Ben, and if her plan does not work, she would not bother him anymore in his decision. Gwen also admits that she promised Michael enough mana in return for his help that will keep him at full strength and power for one year, furthering Ben's anger toward her.
Michael explains he saved a part of the Dominus Librium, which can be used to turn Kevin back to normal. However, the machines and energy required to power it is only available at Los Soledad. In order to lead Kevin there, they need bait. Gwen suggests herself. Gwen goes to an abandoned arcade and confronts Kevin. He admits that he has been avoiding her so he will not absorb her energy, which he is desperately hungry for. They fight intensely, and Gwen tries talking some sense into Kevin. Unfortunately, this doesn't work and Kevin grabs a hold of Gwen and absorbs both her magical and Anodite powers, making her scream in pain. Gwen retaliates with a mega blast and escapes.
Michael and Ben travel with Gwen in the Rust Bucket 3 to Los Soledad, where Michael trapped Cooper to create a machine that could operate the Dominus Librium. Kevin goes to Gwen's house in search of more mana but finds Max. Another fight occurs, and just as Kevin is about to kill Max, Harvey, Kevin's step father, stops him. Ben appears after Kevin and Harvey's altercation and fights Kevin, yet again. They destroy the Rust Bucket at which point Gwen comes out. Kevin manages to disable Ben long enough so he can chase after Gwen. After a long chase, Ben returns and fights with Kevin once again.
Kevin defeats Ben, but little does he know that was all part of the plan. Gwen calls Cooper to tell him that Kevin will be there soon. Cooper tries to stall Kevin by using the weapons available at the military base, but Kevin dodges the missiles and approaches. Kevin and Ben fight, with Ben no longer holding back. In anger he almost kills Kevin but Gwen stops him, as they could still bring him back. They finally set Kevin to the machine, and Kevin is healed from his third mutation.
In It's Not Easy Being Gwen, it's revealed that Gwen takes her education very seriously. She is shown to come home late at all hours of the night and wakes up at 5:30am. She is involved in many activities, such as jogging, French, and after school karate classes.