Pentonville Prison. Wally Hibbert is serving a long sentence for arson. But after befriending and tricking one of the officers, Hibbert makes an audacious escape. Inspector Marmion, the detective who arrested Hibbert, is warned to watch his back, but it seems that Hibbert has another target in his murderous sights. However, the investigation is mired in confusion, the identities of killer and victim become increasingly ambiguous. An inmate at an internment...

December 1864. As a cold winter wind scours the Worcestershire countryside, an excursion train comes through a tunnel in the Malvern Hills, only to be confronted by a blockage on the line ahead. The driver manages to slow the train down so that the impact is minimised, but the passengers are alarmed. The first person to alight is Cyril Hubbleday, the man in charge of the excursion. He walks to the front of the locomotive - and, as he is talking to...