The basic premise is that a hair metal band acquires an ancient Egyptian tune which brings things back from the dead. They play it mainly on bass. So whenever the song is played, something nearby comes back from the dead.
They're on a roadtrip and come across Hitler and Eva Braun (who is a werewolf) in an old shack living with their hot daughters and some Nazi midgets. Hitler et al kill them, eventually, only to see the band rise from the grave to combat their evil.