Cambridge, October 1933. Inside the old All Hallows Church on All Hallows' Eve, Doctor Adelaide Hartest bears witness to the final moments of a dying stranger. Despite the dagger plunged into the stranger's chest, the death is ruled a suicide, compounded by a formal confession before death. The victim, it is revealed, is known to Scotland Yard, and Assistant Commissioner Joe Sandilands is sent all the way from London to investigate. Thrown into a deadly ring of cloak-and-dagger politics and high-society hedonism, Sandilands must uncover the truth before the Hellfire Club, an elite society composed of intelligentsia and aristocrats, topples the institutions and harms the people he has sworn to protect—especially one he has come to truly love.