It's three days before Christmas, and the Malworth Amateur Dramatic Society's rehearsal of Cinderella, scripted by GP Carl Bignall, is struggling thanks to a flu epidemic that has hit the production.

But as rehearsals finally get under way at the Riverside Theatre, the police across town are entering Carl's house - and discovering the body of his wife, Estelle . . .

Why was Carl so late for rehearsal? Why is Dr Bignall's neighbour so reluctant to tell the truth about what he witnessed? And why is Dr Denis Leeward, Carl's partner, sitting in his car, slightly bruised and in a state of guilty panic?

All Detective Chief Inspector Lloyd knows for sure, as he takes charge of the investigation, is that one of them is a murderer . . .