The game is based on the works of H. P. Lovecraft, author of "The Call of Cthulhu" and progenitor of the Cthulhu Mythos. It is a reimagining of Lovecraft's 1936 novella The Shadow over Innsmouth, taking large inspiration from another novella called The Shadow Out of Time as well as Chaosium's Call of Cthulhu role-playing game 1997 scenario Escape from Innsmouth. Set mostly in the year 1922, the story follows Jack Walters, a mentally unstable private detective hired to investigate in Innsmouth, a strange and mysterious town that has cut itself off from the rest of the United States.