Lizzie tries out for cheerleader but doesn't do very well. Later that night she and Miranda chat online. Lizzie jokes that Kate made the squad because she stuffs her bra. Miranda accidentally sends out the message to everyone on the class roster. The next day at school Kate is furious about the taunting she's receiving and confronts Lizzie and Miranda, demanding to know who is responsible. Lizzie stutters and stammers for a few moments, then Miranda says that she did it. Kate promises to make her life miserable, and a war of dirty tricks breaks out between the two. Miranda tells Lizzie that she took the blame because Lizzie can't handle conflict. Lizzie feels guilty as the war between Miranda and Kate escalates. Finally Lizzie works up the nerve to take responsibilty for the message and she stands up to Kate. Also, Matt brings home a lizard for a school project and names it Lizzie, much to his sister's annoyance. While Mr. and Mrs. McGuire are supposed to be watching the lizard, it die

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.