Mark asks Callie to take their relationship to the next level, but his romantic gesture is threatened when her psychotic, prankster ex-boyfriend returns to win her back.
Lady Hoo-Ha, America's most adored pop star, goes zombie, and her many devoted fans follow suit. Mark befriends one of the newly zombified, and Randall doesn't take it well.
Callie is promptly promoted after turning into a man, causing strife in her relationship. The gender politics are further frustrated by a trip to Atlantis.
Randall's new arm makes him the perfect quarterback ringer for the DOI's intramural football team. Callie pimps out Leonard to raise money for a new sports car.