When the circus arrives in Edinburgh, Rose McQuinn is delighted. However, the much anticipated festivities are overshadowed by a curious set of crimes, involving the murder of a clerk during a bank robbery and within hours of each other, the identical suicides of two young women. Are these deaths as straightforward as the police claim or could they all be linked to one killer? Reluctantly, Rose decides that this investigation is beyond the powers of a Lady Investigator. But fate rules otherwise with the unexpected arrival of her ex-fiance Inspector Jack Macmerry, on a fraud case that might have possible connections with the recent deaths. He believes that Rose can help with his inquiries and she finds suspicious links with the circus and the behavior of a sinister scar-faced clown. The evidence leads her from suspect to suspect but Rose still cannot prove conclusively who the real killer is. She confides in her new-found friend - young, rich and beautiful Elma Rice - and together they sift through the circumstantial evidence. But when there is a murderous attack on Elma's husband, Rose must discover what vital clue she has overlooked before she becomes the killer's next victim.