Malcolm's writings detail an obsessive investigation into a submerged, ancient house lying beneath the lake—one that has long been the center of local legend and tragedy, including the drowning of Mara's parents. As Mara uncovers more, aided by a group of unlikely allies—including Noah Carlyle, a descendant of the town's founding family—she learns of an ancient, non-human intelligence connected to the lake. This entity, once contacted during a failed ritual in 1952, is now reawakening as the lake recedes and the submerged house rises. Marked with strange glowing symbols, Mara and others become entwined in the entity's plan to return. As the house emerges and townspeople fall under its call, Mara must confront forgotten memories, ancestral ties, and a destiny that suggests she is the key—the "gateway"—for an ancient power long hidden beneath the water. The story blends mystery, horror, and sci-fi, culminating in a chilling revelation: the entity has been waiting for her.