Petty crook Eddie Cass is paid £100 to deliver a parcel to Regent Park West. When nobody answers the door, Eddie goes against his instructions and opens to discover a human head.

Eddie goes on the run with aid of Hugo Silver, who informs him that his estranged wife Dana is a murderer and has set him up. Silver persuades him to infiltrate the rich elite but he's then murdered and Eddie has no allies.

Eddie is forced to live on the street then gets a break when he spots Jill. She leads him to his friend Caractacus but he has changed. After getting him fit for battle, they take him to a meeting but Jill has betrayed them all.

Eddie can't get arrested and his one lead is a house in Holland Park. He enlists the owner's daughter and they head to a country house where he discovers the real killer is too important to ever be named and has just one choice.