After a brief and ill-advised dalliance with the Suffragette movement, Lady Rose Summers' debut season in London society turns out to be a complete disaster. Rose's father suspects that her fiance, Sir Geoffrey Blandon, is a first class scoundrel and calls in Captain Harry Cathcart to investigate.

But when a malicious guest is found dead in suspicious circumstances, Rose becomes far more interested in discovering the truth than in landing a more appropriate suitor. As Harry and Rose begin to unravel this web of lies and rumours, a clever murderer sets out to make Rose's disastrous first season her last.