Robert Mitchum stars as a Boston gangster in this crime thriller directed by Peter Yates. The film follows delivery truck driver Eddie Coyle who moonlights as a low-level gunrunner for a Boston gang. After being busted for a truck hijacking, Eddie's only hope of escaping jail is to snitch on his friends of the criminal underworld. While he passes information to the authorities, through ATF agent Dave Foley (Richard Jordan), Eddie continues to supply guns to would-be bank robbers. How long will he be able to continue playing both sides?