January 1910. A journalist has been killed in a suspicious blaze. Everything points to a group of suffragettes, but the apparent culprit insists she is innocent.

When Lady Hardcastle receives a letter from a suffragette requesting her urgent help, the retired spy turned sleuth knows only she stands between an accused young woman and the gallows. Evidence at the scene makes Lizzie Worrel’s innocence difficult to believe, and with the police treating it as an open-and-shut case of arson, Lady Hardcastle faces a barrage of resistance as she tries to dig out the truth.

With her trusted maid and confidante, the formidable Flo, Lady Hardcastle sets off in pursuit of the truth as time runs out for the accused suffragette. Was she set up? And if so, is the real culprit a traitor to the cause—or part of a darker conspiracy?