The online version takes the form of a Victorian periodical or newspaper, which includes various advertisements that reference characters such as Vlad Tepes, Victor Frankenstein, Spring Heeled Jack, and Dr. Jekyll.
[2] The unnamed narrator, a veteran of a bloody war against the "gods and men of Afghanistan", whose arm has been gravely injured by torture, is seeking lodgings upon his return to "Albion"; he becomes the roommate of a man of extraordinary deductive skills who puts them to use as a 'consulting detective'.
Early in their acquaintance, Inspector Lestrade of Scotland Yard arrives at their lodgings in Baker Street, hoping to hire the narrator's roommate to solve "a matter of national importance".
The roommate insists on bringing the narrator; they investigate the murder scene, and the detective correctly deduces that the victim is of German royal blood, having an inhuman number of limbs.
The investigation takes the detective and the veteran to a music hall show, starring a noted actor called Sherry Vernet.
A "tall, languid" man, Vernet stars in three productions, including a historical narrative depicting the war between humanity and the Great Old Ones.
Posing as a theatrical agent offering to take the show to the New World, the detective meets Vernet and quickly determines that he and another, a man with a limp and skill with surgical equipment, were present in the room where the German noble died.
He reveals what he has deduced: that Vernet is a seditionary "Restorationist", an anarchist who believes that the Great Old Ones are not the benevolent rulers that they claim to be, but vicious, soul-destroying monsters from whom humanity must be freed.
The veteran does not do so, instead adding a copy of the letter and an account of the investigation to his bank deposit box, not to be opened until everyone involved in the case is dead.