Only a few hours after an unfortunate one-night stand, Riley, a social worker, realises that just like Samantha, he too is infected with the necrotic STD, experiencing ominous angry symptoms of the abominable malady. Furthermore, as the highly contagious disease devours his feeble flesh, desperate Riley must try to locate the original patient zero throughout the city of Los Angeles with the intention to find a cure, while at the same time, a driven detective is after him. But in the meantime, the virus keeps spreading while the plague's original carrier is still on the loose.