Lizzie, Miranda and Gordo all have big problems on the day their pictures are to be taken for the junior high yearbook. Lizzie searches and searches for the right thing to wear, but her mother insists she put on a ""hideous"" sweater that her grandmother gave her. Miranda runs afoul of Kate when they both show up wearing the same outfit. And Gordo feels the pressure to assume a tough-guy pose when his picture is snapped. Meanwhile Matt hasn't studied for a quiz at school, so he fakes being sick to get out of it. But he finds out that his mom's cure can be worse than the disease.

Lizzie is looking forward to the science class field trip, but she is mortified when she finds out that her mother is a last-minute replacement as the girls' chaperone. Lizzie fears that her mother will embarrass her to death, and Mom does a pretty good job of doing just that while they are competing with the boys on a nature walk. But Mrs. McGuire proves how cool she can be when she helps the girls get back at the boys for a prank they pulled then takes all the blame herself. Back at home, Matt and Mr. McGuire are left on their own and try to cook for themselves.

Lizzie and Miranda are ecstatic about being invited to a pool party given by their heartthrob, Danny Kessler. Mrs. McGuire is excited for Lizzie too until she finds out it's on the same day as grandma's 80th birthday party. She tells Lizzie she has to go to her grandma's instead and Lizzie is furious. The next day at school Miranda temporarily gets on the good side of Kate, the girls' former best friend who has literally and figuratively outgrown them. Kate invites Miranda to hang out with her crowd, causing a conflict between Miranda and Lizzie. At home Lizzie catches her mom on the phone making up a lie to get out of a commitment and accuses her of being a hypocrite. Gordo helps Lizzie to smooth over her differences with Miranda. Mom tells Lizzie she can go to the party after all, but she decides not to and spends the day with Gordo.

Lizzie is dissatisfied with being an ordinary ""B"" student and is looking for something at which she can excel. Surprisingly, she finds out in gym class that she has a real talent for rhythmic gymnastics. But she thinks the sport is stupid and is ambivalent about competing. She trains hard and goes to the regional competition, where a jealous Kate tries to sabotage her performance. Miranda and Gordo help foil Kate's plan and Lizzie wins first place. Her parents are proud but Lizzie decides to give up the sport and go back to being her ""ordinary"" self.

Gordo is sure that Mr. Pettus is giving him ""B""s instead of ""A""s because Pettus doesn't like him. His state of mind isn't helped any when the teacher gives the class an aptitude test which shows that Gordo is best suited to be a blackjack dealer. To prove that Mr. Pettus has it in for him, Gordo convinces Lizzie to turn in his science project with her name on it and vice versa, which ends up having disasterous results. Also, Matt adopts a hip-hop attitude and insists that everyone call him ""M-Dogg.""

Lizzie and Miranda are excited about the news that singer Aaron Carter is coming to their town to do a video shoot. They enlist Gordo to help them figure out where the shoot will take place so they can crash the set and meet Aaron. Matt horns his way into the group also. When they arrive at the site Matt is mistaken for Aaron's stand-in and let on the set, but the other three are not. They try several ways to sneak in but are always chased off by a security guard. In all the confusion Mr. and Mrs. McGuire somehow manage to get detained by security. Aaron's manager catches the trio and Lizzie convinces her to at least let one of them meet Aaron. She agrees, and Lizzie tells Miranda that she can be the one. Lizzie goes back to get a tape recorder she left behind and runs in to Aaron, who gives her a kiss. The kids all get to be extras in the video.

When a babysitter cancels on the McGuires, Lizzie suggests that she's old enough to do the job for her brother Matt, but mom and dad say no. After much persuasion from Lizzie they relent, and Miranda and Gordo also come over to help. After Mr. and Mrs. McGuire leave, Matt generally causes havoc, spilling grape juice on the rug, acting bratty and taking advantage of Lizzie, who badly wants to impress her parents with her responsibility. Miranda and Gordo aren't much help as they won't follow Lizzie's orders either. At the restaurant Sam McGuire wants to sneak home and check on his daughter and son; Jo doesn't like the idea, but says just don't let them see you. Meanwhile at the house, Matt has knocked out the power. Mr. McGuire tries to peer in the window and goes tumbling over. The kids think he's a burglar and call the police. Mr. McGuire tries to get in the locked house and the kids wage a battle against him reminiscent of the movie Home Alone. The police come to arrest Sam. After al

Lizzie and friends are frustrated--the only candidates for school president are super-popular cheerleader Claire Miller and oddball Larry Tudgeman, who promises to eat a worm for every vote he gets. Gordo encourages Lizzie to run as a ""normal"" candidate and Miranda seconds the motion. Lizzie agrees to do it. Gordo is her gung-ho campaign manager as she runs on a ""voice of the people"" platform. Lizzie starts to gain confidence, even enough to tell off Claire and Kate. Gordo thinks she should schmooze the ""second-tier"" popular kids in the drama club, so Lizzie puts on her shades and black leather and tries to get in good with them. Miranda is annoyed that Lizzie is blowing off the less popular kids and groups to hang with the drama club. Lizzie starts to develop a prima donna attitude and now Gordo has to agree that he has helped create a monster in candidate Lizzie.

Mrs. Stebel pairs up the students in her social studies class for a mock marriage assignment. Each set of partners must draw a job from a jar at random, work up a fictional lifestyle and report back at a pretend 20-year reunion. Always-snobby Kate is horrified to find herself matched up with Larry Tudgeman, but at least she likes her job, a television anchorwoman. Lizzie wants to be partnered with Ethan Craft, who's not so smart but is cute. But she gets familiar old Gordo, whose job is sanitation engineer (garbageman). Lizzie figures it's not so bad, though, since Gordo will probably ensure she gets a good grade. Her mind begins to change when Miranda gets picked to be Ethan's partner, and he's a surgeon to boot. Lizzie can't help but be jealous.