Preparations for Santa Louisa's annual spring rummage sale are thrown into chaos when organizer Mary McGill and her devoted cocker spaniel Millie come across a dead body on the premises. Still wearing her pink nightdress and slippers, what on earth was Miss Emilie Plym doing in a locked church hall in the dead of night? And who on earth would want to harm a sweet-natured but confused elderly lady who wouldn't hurt a fly?

As Mary questions the victim's nearest and dearest, she discovers that not everyone had Miss Plym's best interests at heart, and that at least one of those who should have been caring for her is hiding a shocking secret.