The Professionals Season 4 Episode 10
A drug addict is murdered by a pusher who then hastily discards the gun, only for it to be found by a young boy-who then accidently shoots his friend in the process. The pusher then goes in search of the boy in an attempt to retrieve the gun and at the same time has to try to avoid his own people who are in pursuit of him.
Serie: The Professionals
Episode Title: The Gun
Air Date: 1980-11-09