Alcoholic detective Jack Sullivan struggles with his inner demons while trying to track down a vigilante serial killer.

After his last assignment ended with the death of an innocent woman, a hitman's new job in London is compromised when he is overcome with guilt, and ends up helping a desperate woman who is caught up in a human trafficking operation.

Four seasoned killers and one hapless professor are rounded up in one violent swoop and awake in chains to discover they are part of a demented experiment orchestrated by their maniacal, mysterious captor.