Alleyn investigates murder in an artists' colony, when model Sonia Gluck is mysteriously stabbed to death while posing for a life class. Before he can catch the killer, Alleyn falls heavily for his prime suspect, the high-stepping painter Agatha Troy, whom he had met once before on a passenger liner sailing home from the South Pacific. Unhappily for Alleyn, Troy looks down on him and his policeman's life. Assisted by the plain-speaking Inspector Fox, after a second death Alleyn finds he is dealing with blackmail as well as murder.