The MIT investigates the murder of Penny Wake who is found by the river. Forensic evidence shows that the woman was strangled and had been dead for several days and that the body had been moved. The killer also went to great lengths to clean the body before disposing of it. They immediately focus on the woman's husband Neil Wake, who says he has been away from home for a week or so on business but it turns out, was actually on leave having spent a few days with his girlfriend. The investigation takes a different turn when a second abduction victim, Kathy Monroe, is found wandering the streets in her underwear. The key however is that both women had red hair.