All Grown Up!

Susie, feeling overlooked by the popular crowd, attempts to shed her "goody two-shoes" image by embracing rebellious behavior.

Chuckie thinks Kimi is unhappy with the way her room looks and convinces the group to redecorate it for her while Angelica distracts her. Despite Dil's attempts to help, his suggestions are overlooked, and it is eventually revealed that Kimi is actually missing her home in Japan and her biological father. Chas and Kira prepare a special surprise to cheer her up.

While the group tries on Halloween costumes in the Finster's garage, they discover mysterious graffiti that leads to a misunderstanding between Tommy and Chuckie, causing a rift in their friendship. The others attempt to reconcile them but end up making things worse. Their friendship is restored when Chuckie rescues Tommy from bullies at the middle school.

After Chuckie's favorite comic book featuring Armadillo Dave is cancelled, he becomes too upset to help Tommy with his science fair project. Tommy ends up with a difficult rat for his experiment, which frightens everyone. Kimi builds him a basic track, but Tommy needs Chuckie's help to improve it and achieve a good grade. The group attempts to find a new hero for Chuckie to admire.

Angelica becomes infatuated with a charming substitute teacher when her regular teacher goes on maternity leave and attempts to impress him by deliberately failing her schoolwork. Meanwhile, Tommy, Phil, and Chuckie participate in the school tennis club, where Chuckie overcomes his fear of the boys' locker room.

Tommy appears indifferent when his girlfriend Rachel moves away, but his friends believe he is in denial. As they try to support him, Tommy becomes increasingly frustrated and tries to move on by dating someone else. Rachel unexpectedly returns, sees him with another girl, and leaves again, causing Tommy to finally confront his true feelings.

Kimi starts a campaign to ban cell phones at school, but Angelica enlists Chuckie to oppose the ban, while Susie supports Kimi. Tensions rise when Chuckie exposes Kimi's secret desire for a cell phone during a school debate, causing a rift between them. With the help of Tommy, Angelica, and Susie, they reconcile at Java Lava after watching a video of their parents' wedding.

While Stu and Didi are away at an Invention Convention, Dil plans a viewing party for a fake alien autopsy video with Tommy, but things get complicated when both Grandpa Lou and Grandpa Boris arrive to babysit. As tensions rise between the grandpas, Phil, Lil, and Chuckie join the gathering, and Dil's decision to invite ten more kids causes further chaos and frustration for Tommy.

Tommy and his friends, whose parents have banned television for excessive viewing, attempt to regain access by building a risky treehouse with a zip line in their backyard, hoping to provoke a strong reaction from their parents.

Tommy skips a traditional opening day baseball outing with his grandfather, Lou, to reconcile with his ex-girlfriend Rachel, prompting Lou to take Dil instead. The decision sparks jealousy in Tommy, leading to a competition between him and Dil to be Lou's favorite grandson during a fishing trip.