Walter Mancini (Nero), an alcoholic reporter, and his wife Eve (Cléry) are on a road trip with a Travel trailer heading back to Los Angeles. Along the way, they pick up a hitch-hiker (Hess) who introduces himself as Adam Konitz. Konitz soon turns out to be a sadistic escapee from an institution for the criminally insane, and he is running from the law after robbing two million dollars with his partners. He takes the couple hostage and orders Eve to head to Mexico. They are soon stopped by two policemen and after Walter attempts to signal them by writing "SOS" on his matchbox, Konitz shoots them both.