Senator Walter Chalmers (Robert Vaughn) is aiming to take down mob boss Pete Ross (Vic Tayback) with the help of testimony from the criminal's hothead brother Johnny (Pat Renella), who is in protective custody in San Francisco under the watch of police lieutenant Frank Bullitt (Steve McQueen). When a pair of mob hitmen enter the scene, Bullitt follows their trail through a maze of complications and double-crosses. This thriller includes one of the most famous car chases ever filmed.