Evan Goldman is a twelve-and-a-half- year-old New Yorker who is going through some major life changes: his parents are getting a divorce, he's been forced to move to Indiana, and his Bar Mitzvah is coming up ("Thirteen"). At least Evan has one friend in his neighborhood, Patrice, and he explains how important it is that his Bar Mitzvah is the best party ever - but Patrice explains that Appleton, Indiana, does not have much to offer ("The Lamest Place In The World"). Although she feels bad for Evan, she's glad he's come to her town, since now they're friends.

Evan plans to ask popular football star Brett Sampson to come to his party. Brett, Malcolm, Eddie, and a few other Guys are helping Brett prepare to talk to Kendra ("Hey Kendra"). When the guys don't have any ideas, Evan suggests that Brett take Kendra to a scary movie. Brett dubs Evan "the Brain" and stops Kendra and Lucy to invite Kendra to the movies on Friday night. Lucy interferes, saying that Kendra already promised to do something with her, but it's obvious that Lucy is lying. Evan is convinced that Brett will attend his party and says as much to Patrice, who tells Evan that it won't be fun because those guys hate her. Evan assures her that they don't know her like he does.

Evan passes out his party invitations on the first day of school ("Invitations"). Brett accepts, and so do Cassie and Molly - until Lucy notices that Patrice also has an invitation. The kids say they won't go if Patrice will be there, so Evan takes her invitation and rips it in half. Patrice is devastated.

Archie, who uses crutches due to muscular dystrophy, tells Evan he can make things right with Patrice if Evan gets him a date with Kendra. He says that Evan, as the new kid, has access to social groups in the school in a way that no one else does ("Get Me What I Want").

In the gym, Lucy, Kendra, Charlotte, and the GIRLS are at cheerleading practice. Through Lucy's point of view, we learn that she's jealous of Kendra and will do anything to go out with Brett ("Opportunity").

Archie finds Patrice in the library, writing in her journal. Archie tries to convince her to give Evan another chance, but she is very hurt ("What It Means To Be A Friend").

The next day, Brett asks Evan to get everyone Friday movie tickets for The Bloodmaster, an R-rated movie. The Kids watch as Evan figures out the logistics. He goes to Archie for help, and they succeed ("All Hail The Brain"). Evan invites Patrice to the movie, and though she's still mad at him, the prospect of going "out" with him is too good to refuse.

Suddenly, Evan realizes he's set both Archie and Brett up on the same date with Kendra. He tells Archie that all he can do is sit by Kendra, and Archie agrees. On Friday, Archie is late, so Evan sits in his seat to save it. Patrice, sitting in the back row, tells him that Archie is in the arcade "waiting for the perfect moment." Everyone is distracted by the gory movie as Brett wonders if Kendra likes him, Kendra wonders the same thing about Brett, and Patrice feels ignored by Evan. Finally, Archie enters, wearing a suit and carrying a bouquet of flowers. Archie takes his seat next to Kendra, and both he and Brett prepare to kiss her - just as Lucy pulls Kendra out of the way ("Any Minute"). Archie's and Brett's mouths meet, and RICHIE takes a photo of the moment. Archie tells everyone that Evan set him up on a date with Kendra, Brett tells Evan that no one will come to his party, and Kendra leaves. Lucy takes the opportunity to kiss Brett.

Evan laments that none of them will come to his party now, and Patrice is angry that he still cares what the others think - and that he paid no attention to her at all on their date. She storms off, and Evan swears that Archie is going to help him fix everything.

The next day at school, Malcolm and Eddie realize that Brett is being completely controlled by Lucy ("Bad Bad News"). Evan decides that if he can get Brett back together with Kendra, he'll be the hero and everything will be forgiven. He convinces Malcolm and Eddie to take him to Brett, even though Brett wants to beat him up. Archie sends Patrice after him to help, and she and Evan suggest that Brett tell Kendra how he feels ("Tell Her"). Brett interrupts a fight Lucy and Kendra are having over him and declares his feelings for Kendra - but Lucy gets revenge when she starts a rumor about Kendra and Evan ("It Can't Be True"). Lucy sets Kendra up to be caught with Evan and prove the rumors true. Brett catches them and threatens Evan, but Evan realizes that Brett has been a terrible friend all along and was never going to go to his party. He calls Brett a jerk, and Brett punches him.

Evan apologizes for taking so long to realize that Archie and Patrice were his true friends. Even though his Bar Mitzvah isn't the huge party he'd dreamed of, he has his friends, family, and parents together. He realizes that even though things aren't always perfect, they can still be okay ("If That's What It Is"). The whole cast returns to bow ("Brand New You").