Jimmy Sutane, a popular musical comedy star is to appear in a show based on a book by a friend of Campion. He is also being plagued by a series of practical jokes that are beginning to undermine his self-confidence and asks Campion to his house,White Walls, to investigate. Associates of Sutane and his wife Linda number 'Squire' Mercer, a talented musician and Chloe Pye, a washed-up actress.When Chloe is run over and killed by Jimmy Sutane in his car he swears it was an accident, but others are not so sure.
A second death occurs, that of Sutane's under-study, who had been playing the tricks on him to get out of the way so that he could take the lead role. Attracted to Sutane's wife Linda, Campion is not wholly convinced of Sutane's innocence until it is discovered that 'Squire' Mercer and Chloe Pye had once been a married couple and that she had come onto the scene to get back with him.
At the Golden Quill publishing house Paul Brand is at odds with his partners the Barnabas cousins - notably stuffy senior partner John - over publication of a rare manuscript by William Congreve. Then he is found murdered, locked in the firm's basement with a hose piping poisonous car fumes through a hole in the window. Michael Barnabas, a friend of Campion, is in love with the dead man's wife who, at the inquest, makes it clear that she and her husband were filing for divorce. Consequently Michael is charged with the murder.
Trying to prove his friend's innocence Campion makes several discoveries, including the fact that the murder was an exact copy of one in a book published by the Golden Quill. The dead man also had a mistress, who tells Campion that there was more than the one key to the basement and that Paul Brand had recently had one cut for himself. Plainly Brand was murdered because he had found out something about the William Congreve manuscript which somebody wanted keeping quiet.