The famous tale of Marcia's first house party, which almost doesn't happen after she is accused of scrawling an unflattering picture of her teacher in class. Marcia's brothers conspire to ruin the party, with the predictable result.
Marcia goes gaa-gaa over her first steady boyfriend, nerdy insect collector Harvey Klinger. Things progress so quickly they decide to start thinking about their future, leading Mike to subtly intervene.
The boys find a wallet with $1,100 in it and no identification. The boys want the money for themselves, the girls want the boys to split the money with them, but Mike turns to the police to help the owner find the wallet.
School bully Buddy Hinton makes fun of Cindy for her lisp and then gives Peter a black eye for trying to defend her. When Mike and Carol can't get Buddy's parents to listen to reason, Mike encourages Peter to defend himself and fight back.
Peter is going to miss a big camping trip after he breaks Carol's favorite vase. Each brother and sister confesses to keep him out of trouble. Mike and Carol figure out the truth and respond with an appeal to Peter's conscience to confess.
Peter, Jan and Cindy make the Glee Club but Bobby does not, so Carol buys him a drum set to make him feel better. Peter's football teammates make fun of him for being a singer, until NFL star Deacon Jones sets everyone straight.
Cindy is spooked after seeing a disappearing act at a magic show, and refuses to sleep in the dark. So Peter puts together a magic act of his own with Cindy as his assistant to help her overcome her fears.
The Bradys fight to save Woodland Park from closing to make way for a new building. But Mike's firm gets the project and he is in charge of the plans for the new building, and Mr. Phillips delivers the family an ultimatum.