Dracula Dossier is a campaign for the Gumshoe-powered RPG Night’s Black Agents, and I can confidently say it’s one of the biggest, most ambitious RPG campaigns ever conceived.

This is the Director’s Handbook (2015), which sits at the center of a shelf of books that make up the campaign. In addition to the rulebook, there’s a modified version of Bram Stoker’s novel, an agent field guide and a book of supplemental scenarios. The conceit here is that the events of the novel are real, sort of. It’s a cover story written to obscure the true events, which were part of a larger intelligence operation against Dracula and his network. Dracula didn’t stay dead and has popped up a couple times since. The modified novel was in the possession of agents who opposed the Count each of these times, and contains annotations in many hands collecting new information and theories.

Here’s the brilliant part. The campaign starts by giving the players the annotated book. The structure of the game builds off their default knowledge of Dracula in all his pop cultural forms. As they chase down the leads in the annotations, they determine the truth of the campaign’s core conspiracy and all of Dracula’s secrets. The GM reacts to their sleuthing, improvising the results based on the dizzying resources in the Director’s Handbook. From there, the campaign is as big or as small as everyone at the table wants it to be.

It’s one of the most interesting RPG books I’ve ever read. It exists as a sort of codex of parallel universes, codifying just about every possible option players might choose, and takes them to their logical conclusions. Some of the early chapter titles give a sense of the overall construction: “Do Vampires Work the Way Van Helsing Thought They Did?” and “Is Jack the Ripper Involved Somehow?” Those two alone open up mind-boggling possible paths, and there are still 200+ pages to go. It’s a beauty, but I’d want to play it rather than run it, for sure.