Britain, beset by the first world war -- and out in Machen country a series of unexplained murders occur. There"s no sign of who or what is responsible. "Explosion at Munition Works in the Northern District: Many Fatalities." The working man told about it, and added some dreadful details. Corpses so terribly maimed that coffins had been kept covered; faces mutilated as if by some gnawing animal. . . . we took a tram to the location of the disaster; a raw and hideous shed with a walled yard about it, and a shut gate. The roof was quite undamaged -- this had had been a strange accident. There had been an explosion of sufficient violence to kill work-people in the building, but the building itself showed no wounds or scars.