Casey seems to have it all - she's in the best sorority, has the most popular boyfriend, and is in-line to become the next President of her sorority that is until her dorky brother, Rusty, comes to school and is determined to join a fraternity.

It's mating season and no one seems to be having a good time. Rusty has to come up with a date for a Kappa Tau party but since just talking to a girl turns him into a blithering idiot, it's going to be hard to convince someone he's appealing. So he turns to Casey for help.

Rusty finds out a secret about Dale's high school friend and fellow Purity Pledge member, but is uncertain to tell Dale what he knows. Meanwhile, Ashleigh, as the new ZBZ president, finds herself in the middle of a battle between Casey and Frannie as they pursue the Omega Chi's for partnership for the coming school year.

Casey faces a hard decision when she learns that Max is planning to go to Cal Tech for grad school and she is offered an internship. She turns to Lauren Conrad (who appears in a dream sequence) for advice. Also, the pledges are put through Hell Week and Rusty is driven to face the challenge no matter what he is forced to do.

In the series finale, the Kappa Taus try to stop the demolition of their house. Meanwhile, Cappie and Casey come to a realization about their on-again, off-again romance; and Cappie and Evan determine whether their friendship is meant to last.