This Peter Maris action begins at New Mexico State Penitentiary, where a spew of toxic gas from the crash of a tanker truck leads to the evacuation of the prison by the warden (George Kennedy). In the ensuing confusion, anti-social cons Kuttner (Lee De Broux) and Patch (James Tolkan) kidnap prison psychologist Maria Slayton (Kim Delaney) and hit the road with a bus full of prisoners. The group first heads for Mexico but decides instead to take over the town of Sonora and hold its citizens as hostages. The National Guard sends in a state police lieutenant (Yaphet Kotto) and his tough-as-nails Lieutenant Colonel Johnson (Jan-Michael Vincent) to handle the situation. But the National Guard's ineffectual methods leave the situation more volatile than it was before. It is left to two citizens of Sonora -- sheriff Ike Slayton (Brad Davis) and his army pal Bill (Ken Foree) -- to take matters into their own hands and save the town from the kill-crazy prisoners.