1860, Wimborne, Dorset. Rebecca Tullidge, miserably married to her callous husband, finds some escape through a love affair with another man. After putting her drunk husband to bed one Saturday night, she sneaks from their lodge to meet railway officer, John Bedloe. But much to her horror, she trips over her love's corpse on the railway tracks. The railway director calls Inspector Colbeck and Sergeant Lemming in from London to solve the hideous crime....

"1862. A goods train is going through the Sapperton Tunnel when it hits a makeshift pen of sheep inexplicably set up near the exit. The animals are slaughtered by the impact whilst the train hits a pile of rocks and is derailed, seriously injuring the occupants. Inspector Colbeck is called in to investigate and discovers that the shepherd and his dog are missing. Stephen Ryle who owned the sheep is shocked by the occurrence which further affects him...