When a young woman is found dead, she is initially believed to be a prostitute and the latest victim of a serial killer. When looking into her home life, Benson and Stabler realize that she does not fit the pattern, and may not be connected to the other deaths after all. However, the other deaths have a connection no one anticipated. While investigating the earlier victims, Munch's instincts lead the team to believe their suspect might be a cop. Captain Cragen talks to his old friend Det. Lennie Briscoe to get his opinion on their prime suspect (a vice cop), but Briscoe informs Cragen about another vice cop named Ridley, who happens to be the partner of the prime suspect. Cragen tells Benson and Stabler to look at this new suspect and Benson discovers more victims. They arrest Ridley, who proudly confesses to all of the killings, but surprisingly he claims the last one wasn't his. Cragen, Benson, and Stabler realize their victim doesn't fit Ridley's pattern; Benson and Stabler are forced to go back through the victim's life to find her killer, who they now believe knew the victim.