Before she was a detective, before she was a reluctant wife and distracted mother, before she was even a debutante, Dandy Gilver spent one perfect summer with the Lipscotts of Pereford. The golden memories of it have sustained her through many a cold snap in Perthshire.

So when two of the Lipscott sisters beg her to help the third, she can hardly refuse. Sweet, pretty Fleur Lipscott: where is she now? The astonishing answer to this is that Fleur - still Miss Lipscott, indeed more Miss Lipscott than ever - is buried alive in the tiny seaside village of Portpatrick, working as a schoolmistress at St Columba's College for Young Ladies.

But she is one of the few remaining, for St Columba's has been shedding mistresses as a snake its skins and the exodus is far from over.

With mistresses vanishing and corpses mounting up, can Mrs Gilver, detective, pass herself off as Miss Gilver, English mistress, to solve the one and stop the other?