Guy Fawkes Night, 1857. Joel Heygate is the popular stationmaster at Exeter St David's railway station. But when the charred remains of a body are discovered in the embers of the town's annual Bonfire, everyone is horrified when it becomes clear that they belong to Heygate. Mr Gervase Quinnell of the South Devon Railway contacts Scotland Yard for their support, and Railway Detective Inspector Robert Colbeck and his assistant arrive in Exeter with all due haste. As Colbeck closes in on the killer, he finds himself in mortal danger - can justice prevail?