Mac and Stella investigate the murder of a college student found decapitated, her body hung upside down from a ceiling fan. The grisly crime occurred during a sorority party and most of the witnesses are too drunk to remember anything. Later, another victim is found impaled on a tree in Battery Park, his eyes gouged out and two railroad spikes inserted into his head. Both victims were wearing unique shirts that contain hidden codes that could provide clues to the killer's identity.