Lady Dyke disappears mysteriously, and barrister and hobby detective Claude Bruce appears to be one of the last persons to have seen her. A short time later a dead body is found in the river, and Bruce follows the trails. Who is Sydney H. Corbett? Why did the Lady's maid disappear shortly after her Lady? And what business did Lady Dyke have at Sloane Square? If Bruce can find the answer to these questions, he will find the solution to the mystery. (Introduction by Carolin)