Episode 412, "Knuckle Up" Friday, May 24, 12|11c
SEASON 3, EPISODE 315 - 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 8 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.