When seventeen year-old Andrea McWilliams is found strangled and beaten to death in an alley, her ex-boyfriend leads the cops to a website that McWilliams used to meet up with random men. Detective Olivia Benson decides to create a user account for the site and finds womanizer Peter Butler, the man who met up with McWilliams. The case is closed when a different suspect is proven guilty of her murder, and a new one opens when McWilliams rape kit tests positive for HIV. Not only is HIV spreading as a result of countless attacks, but now the detectives must also catch a rapist on the loose.