S3, E15: When a 1998 drug case is reopened, Valens becomes the focal point. He had worked undercover on the high-profile case, and now he must face the demons that have been haunting him for the past eight years. At the time, he got too close to a lady friend who was being used to courier drugs and it might have cost her life. Everyone on the squad is shocked to learn that Valens had gone undercover and never mentioned it since.