The plot is divided into three acts:
- Book I: The Madman
- Book II: British Gods
- Book III:The Upper House
It is a particularly psychological campaign by CoC standards, with a strong emphasis on the complex relationships among cultist NPCs. Most of them are aligned to Hastur or Shub-Niggurath in some way, but that in no way implies that their goals are usually in harmony with each other. Quite on the contrary, much of the plot revolves around their lack of mutual cooperation and their frequent conflict.
At a late stage of the plot Hastur himself is manifested. Minor NPCs include Aleister Crowley.
Appendix G suggest Bibliography, Sources and Inspirations, including various stories of the Hastur Cycle by Ambrose Bierce, James Blish, Lin Carter (the campaign's name is shared with Carter's Tatters of the King) and August Derleth, as well as Ramsey Campbell's Cold Print; Robert Chambers' The Yellow Sign and other stories: Complete Weird Tales of Robert W. Chambers; and H.P. Lovecraft's The Dream Quest of Unknown Kadath.