A classic mystery/detective story in the Sherlock Holmes tradition, the hidden room suggested by the title of this book does not remain a mystery for very long as the book progresses. Written in the first person, the husband of his (Carlton Davies) former lover is found dead one night at the stroke of midnight, and Davies finds his ex-lover standing over the dead body immediately after the shot was fired, with a gun in her hand. It was no secret that she never truly loved her husband, who had blackmailed her into marrying him. The jury ships Ruth to prison, and the stage is set for Davies to locate the right detective for the case, and for a series of events with twists and turns and surprises that will keep the reader guessing who was responsible for this murder.