The young, bright, and decent London tramp Alan Terry (Rupert Graves) accidentally witnesses a mob execution. He gets away, but leaves enough evidence for them to come looking for him amongst the homeless, and most violently: his older best friend is killed by arson. It turns out that Matheson (Sir Michael Gambon), the police Detective Inspector in charge of the murder investigation, is in cahoots with mob boss Adolfo Cavani (Franco Nero), and actually on Alan's trace, with the firm intent to eliminate him. The only one who may actually help Alan is a female reporter.