Mark Hammond is an ex-gangster who wants to forget his past and live honestly with his wife and little son. Everything goes horribly wrong when London's most vicious criminal, the organized crime boss Charlie Jolson, decides that he needs Mark's services and obtains them in a twisted and cruel way: Mark's wife is murdered, he is framed for this murder, and his child gets kidnapped.

Jolson makes it clear: unless Mark does what he orders him to do, the boy dies. Using the helpless man in his plan to bring down other criminal organizations of the city, Jolson sends Mark on suicidal missions during which Mark has three terrible choices: walk away and lose his son, get killed in a battle against overwhelming odds, or single-handedly help Jolson to get rid of his adversaries.

Once the player completes Mark Hammond's story, a new scenario opens, in which the player controls Frank Carter, a vigilante cop who won't stop until he brings Charlie Jolson to justice. Frank's scenario is parallel to Mark's, shedding more light on events that remain somewhat unexplained during Mark's scenario.