Set in the early 20th century, during the winter of 1926-27, the story explores the themes of forbidden knowledge and the horrors of uncovering unsettling truths about existence. Following the mysterious death of Professor George Gammell Angell, his grand-nephew investigates the professor's strange belongings, leading him to cryptic manuscripts and a chilling bas-relief tied to a sculptor, Henry Anthony Wilcox. This journey reveals disturbing links to a monstrous entity, Cthulhu, and a sinister voodoo cult in New Orleans, involved in mysterious disappearances and violence. As Officer Legrasse and his team delve into the swampy depths of the cult's activities, they confront ancient rituals and grotesque beings connected to cosmic horrors, suggesting the terrifying power of Cthulhu lying dormant beneath the ocean. Through various narratives, the characters grapple with madness and the struggle between knowledge and ignorance, ultimately highlighting the existential threat posed by these ancient forces and the peril of uncovering truths that are best left undiscovered. The narrative serves as a chilling reminder of humanity's tenuous hold on sanity in the face of the vast and unknown cosmos.