On the festival planetoid Glastonbury VI, the galaxy's most popular rockers, the Cosmic Kings, are getting ready for the performance of their lives... or, should that be, the end of their lives? Because the drummer's been murdered - with his own drumstick. Hastily enlisted as the replacement drummer, the Doctor leaves Nancy to solve the crime. But who could the killer be? The greedy manager, desperate for publicity? The long-standing rivals, rock band Earth Music? What about the festival's organizer, struggling to cope with the band's outrageous rider? Or the suspicious journalist, with her knack for being in just the right place at just the right time? Or even the bitter band-mates? Time's running out; unless Nancy can act fast, there may be treble ahead.