The team goes to Gwen's house to find a solution to defeat Computron's minions from Dimension 12. When they go to Gwen's room, they find a dark-hair girl. Gwen's mother, Natalie, tells them that it's Sunny, Gwen's naughty cousin. They try to leave the house, but Gwen's mom insists they take Sunny with them. The team takes Sunny to the mission but, they left her in Kevin's car. They go to fight the robots. Ben 10 Sinhala Cartoon becomes Four Arms. Sunny gets bored in the car, and she follows them. She destroys the robots with ease. Sunny is very happy, but the team is looking at her strangely. Gwen tells her mother that Sunny is an Anodite, much to her surprise and disgust.
Then, a big monster knocks on the door. It is Antonio, Sunny's lovestruck boyfriend. Gwen tries to stop Sunny from going with him, but fails. The team goes to defeat the robots, which have returned. During the fight, Sunny comes to have fun and she defeats some of the robots. When Gwen tells Sunny that her parents don't want her dating Antonio, Sunny sheds her human disguise and a fight ensues. Ben 10 Sinhala Cartoon becomes Ultimate Humongousaur and defeats Antonio. Sunny proves to be far much stronger than Gwen, as she managed to immobilize Gwen with her long flowing tendrils of whitish-magenta hair easily. Gwen summons Grandma Verdona through a manna field, who comes and takes Sunny and Antonio back to Anodyne so that their parents can deal with them themselves.
