An underage escort is found dead at a wild bachelor party, and Captain Cragen cautions his team to investigate with discretion, as there were several high-profile people at the scene. In their efforts to question a well-known leader in the New York escort world, Benson and Amaro encounter former SVU detective Brian Cassidy, who's been working undercover. With his help, the detectives dig deeper into a vicious power struggle between the two top escort businesses, but before the case is cracked, a shocking event threatens to destroy the life of one SVU squad member.