The film involves a plot by a present-day (1973) Mafia don (Martin Balsam) to avenge the killings of a group of Mafia dons back in 1931 ("The Night of Sicilian Vespers") with a bold nationwide counter-strike against most of the current Italian and Jewish syndicate heads using teams of Vietnam vets instead of Mafia hit men. ("Stone killer" means a Mafia hit man who is not himself a member of the Mafia.)