Devon O’Brien has a few secrets: He is an assassin who must find the Crown of the Undying, and he killed the sire of the vampire he must serve. Living on an isle overtaken by an imperial power, Devon is tasked with traveling to a dreary, peculiar, and seashell-filled coastal manor in Etierre, and he must retrieve a necromantic artifact called the Crown of the Undying from the vampiric lord of the manor, Naberius, who rules over three other vampires. When Devon, undercover, is assigned to serve the fastidious and dry-humored vampire musician Cillian Gallowglass, the two, despite themselves, grow closer and keep each other moored—but never one to let anyone truly know him, he finds himself in a dilemma: Years ago, Devon murdered Cillian’s true sire, and therefore he’s responsible for all the pain Naberius inflicts on Cillian after he took him in. The discovery of that truth may unravel everything, or in their colliding paths toward freedom, penance, and vengeance, Devon and Cillian may find a way to embrace the worst parts of themselves. The House of the Three-Headed Dog is an M/M dark, sensual, and gothic vampire romance with a trans man assassin lead.