Casey returns with secret plans to move out of the ZBZ house; a new freshman is highly desired as a pledge; Rusty tries to balance studying with life in the Kappa Tau house.

When Frannie challenges the sisterhood of ZBZ girls, and Casey retaliates by challenging the IKI’s to a game of dodgeball. Meanwhile, Rusty struggles with the fact that Dale is so in love with their new apartment that he never leaves, so Rusty enlists the Kappa Tau’s to invade the house to scare him away. But the plan backfires when the landlord shows up the next morning with a tour.

After she falls into a manhole risking her life, coupled with the Kappa Tau's throwing an "End of the World" party, Casey is sent into an emotional tailspin, questioning her relationship with Max and her lingering feelings for Cappie. Meanwhile, Ashleigh faces her own punishment with Pan Hellenic after a complaint is lodged by Frannie for the Homecoming Float sabotage. Ashleigh turns to Casey to help fight the charge, but when Casey gets caught up in her own personal drama, she leaves Ashleigh to face Frannie alone. And with Dale having trouble keeping his cougar girlfriend's sexual advances at bay and Calvin trying his best to resist hooking up with his new hot roommate, Grant. Dale convinces Calvin to go in on a "purity pledge" partnership so they can help each resist their most recent temptations.

The students at CRU feel the ramifications of the Kappa Tau's "End of the World" Party. Rusty risks being dropped from the honors program if he cannot raise his grade in organic chemistry and Casey adjusts to single life.

Casey's detective skills inadvertantly start a brawl between the Kappa Tau's and the Omega Chi's. Meanwhile, Rusty, Calvin, and Dale take a trip to Comic-Con as Ashleigh and Fisher resume their relationship but still have a few issues.