It's the sweltering summer of 1911, and one Friday evening a special train rolls into York station. It carries a young aristocrat recently found guilty of murdering his father in the sleepy village of Adenwold. He is briefly entrusted into the custody of railway detective Jim Stringer, and he warns of another murder likely to happen in the same village - that of his brother, a reclusive intellectual. Jim and his wife Lydia take the train along the near deserted branch line to Adenwold. Here they encounter a host of likely suspects and the intended victim, as Jim has one weekend in which to stop a murder and unravel a conspiracy of international dimensions.