Gwinny Tuffel, preparing for her first West End role in a decade, is continuing to dog-sit to keep the wolf from the door. What should be an easy gig, staying on a Little Venice houseboat to help ageing rock star Crash Double with his Border Collie, takes a sinister turn when the singer's dead body surfaces during the annual Canal Carnival festivities. While the police dismiss the death as an accident, Gwinny suspects murder most foul and it is up to her, with Ace's on-the-ground knowledge, to make sure the killer faces the music.