Charles Bronson re-teams with director Michael Winner – sandwiched between their first pairing in the underrated Chato's Land and their seminal collaboration in Death Wish – in this Lewis John Carlino-scripted actioner. Bronson plays Arthur Bishop, a "mechanic" or hired killer, famed for his efficient and unfeeling contract executions. The young and eager Steve McKenna (Jan-Michael Vincent) teams up with him, hoping that Bishop will teach him the bounty-hunting business. Imparting words of wisdom to Steve like, "Murder is only killing without a license and everybody kills – the Army, the police," the two undergo a series of adventures as Bishop shows Steve the ropes.
A reporter (Terence Longdon) probes the mysterious death of his brother, who fell out of the window of his college dorm room. Without anything to go on, except his own curiosity, Longdon begins asking questions. When the police and the college staff are evasive in their answers, he digs in his heels and starts his own probe. Longdon turns to his brother's classmates and friends. He schedules a meeting with a student who saw someone walking on the roof of his brother's apartment on the night he fell. But minutes before the meeting time, the student is found dead, another victim of an accident. Now even the police are willing to believe that there is more here than just two accidental deaths.