With Mardi Gras celebrations, Casey has a hard time studying; Rusty invites Katherine to the KT party.

The Hilgendorfs have moved next door to the Kappa Tau house, and their presence is putting a damper on the KTs' festivities. When their interferes too much with the fraternity, Rusty and Cappie decide to to bring Professor Tom Hilgendorf in and make him a pledge. But once inducted, Tom doesn't seem to want to leave, leading Cappie to rethink his plans on graduating.

It's Valentine's Day! Casey and Cappie compete over who can come up with the most romantic gift. Also, Casey sets Katherine up with Rusty in an attempt to reconcile with her. Ashleigh is worried that new boyfriend Pete will turn out to be another Fisher, especially after Natalie implies that she and Pete are in a relationship. Evan attempts to bring out Rebecca's obscure romantic side with a special gift. Meanwhile, Calvin is worried that he and Grant are losing their spark, mainly after observing Grant's new beauty ritual.

Casey and a resistant Cappie, try to talk about the future after the "G" word Graduation. The situation gets worse when a handsome Washington politician, encourages Casey to view politics as a career, after she helps him with his voter registration campaign. Is Cappie ready to grow up?

The ZBZ's hear that their candle is responsible for the Gamma Psi fire, and Casey cracks under the guilt, putting the house in danger. Hoping to cheer up the house and boost her marketing major, Ashleigh enlists Rusty and Dale in a philanthropic "Geek Auction", but Casey is the one who has to play dirty to save the house. Can Casey save the day?