Episode four

When the body of a beautiful young woman is found, DCI Gene Hunt fears a serial killer he thought he'd sent down in the late '60s may still be at large. For Sam, the victim, a beauty rep like his Aunt Heather, triggers vivid recollections of childhood. Utilizing his knowledge of modern surveillance techniques, Sam is led to middle-class suburbia, where a local car dealer is throwing private parties employing the poorly paid make-up girls to "help out" when the lights go down and the wife-swapping begins. Sam and Annie go undercover as a young swinging couple to infiltrate the swinging world of Blue Nun and lava lamps.