When The Velvet Miasma self-destructed on stage in the mid-seventies, band members vowed they'd never perform together again. But retro is in, and a promoter smells big bucks in a reunion. Thor, the band's egocentric leader, recruits aging hippie Paladin to dry out the lead guitar player and try to persuade Maggie Thunder, the band’s sexy singer, to join the tour. Meanwhile, Paladin's son, Eugene, replaces a keyboard player blown up on a Mexican drug boat. It’s the kid’s big break, until Thor moves in on his girl.
Paladin discovers why Maggie, now a strait-laced matron, left the band. He promises to keep the dirty secret, but all bets are off when Maggie’s daughter auditions, Thor is found beaten to death with an electric guitar, and Eugene becomes a prime suspect.
With the help of Scan Man, Socks, and a cross-dressing plumber, Paladin and his zoned-out friends muddle their way toward truth, justice, and a killer who gives new meaning to the term “off the charts.”