Undercover cop Tommy Murphy (James Nesbitt, Cold Feet,Jekyll) throws himself into dangerous assignments to escape his painful past. He infiltrates a trigger-happy gang of diamond thieves, gets sent to prison to lure information out of a serial kidnapper, and risks becoming the victim of a murderous female who uses a gym to find her victims. Other assignments–such as acting as the bodyguard for a threatened snooker player–seem less dangerous, but minor problems (a snooker player’s surly manners, for example) swiftly escalate to threaten the lives of Murphy and his superior, DI Annie Guthrie (the excellent Claudia Harrison).