Dr. Grout, a co-founder of a medical research institute, is found with arrows jutting from his back, and the letters "Wy" written in blood on a nearby rock. According to medium Sarah Pensall, the killer is a grim reaper with a crossbow. He’s accompanied by the spirit of a woman, and he will strike again. As associates of the institute are systematically killed off by the hooded specter, Murdoch finally gets a tip - a letter bearing only the word, "Wykeham." Whatever it means, Grout wanted them to know about it. Finally, with Pensall’s help, Murdoch discovers that, in 1893, a young woman died in a fire at Wykeham - a lodge once leased to Grout’s partner, Dr. Greyson.