December 1925. St. Louis, Missouri. Out of cash, out of luck, and soon to be out of a home, Cian Shea scours the Irish neighborhood of Kerry Patch for work. When a job falls into his hands, it seems easy enough: deliver a small, unmarked box to a rich man’s home. The job, however, proves far from simple. Framed for the murder of the local mob boss, Cian’s only chance at clearing his name is to recover the mask and identify the killer. Unfortunately for Cian, he discovers that many people want the box—and, more importantly, the secret it contains. Being hunted by gangsters, bootleggers, and Prohibition agents is bad enough, but Cian finds his steps dogged by sorcerers and spiders and golems who wouldn’t mind pulling him apart (something he’d prefer to avoid). His search leads him to the beautiful Irene Lovell, suffragette and flapper, who is determined to find the box for herself. When a team of supernatural investigators comes to their rescue, Cian learns that there is a great deal more to the world than he had ever imagined and that the box holds an artifact that will rouse an ancient and terrible evil. Before that evil can awaken, they must recover the mask—and they must do so without succumbing to the madness of the weeping lore.

When socialite-turned-detective Irene Lovell finds herself kidnapped by a man she once trusted, she must struggle to free herself. Escape, though, only leads her deeper into the cultic madness and sorcery of the St. Louis underworld. As she works with her friends to stop an unspeakable evil from being awoken, Irene learns that not all of her friends share the same goal. While she seeks to destroy the Drowning Mask, others plan to turn it to their own ends. And others want something even worse: the return of one of the old gods.