The grand Royal Liver Building looms over Liverpool, its iconic twin birds perched like silent sentinels high above the city. For Sam, overseeing the restoration of this historic structure, it is just another project, until the birds’ grotesque forms appear to follow him, their eyes alive with something dark and unsettling. A historian friend, Gwen, warns him of the building’s cursed past, a legend the Liver Birds are not mere symbols of civic pride, but protectors of an ancient seal designed to hold back something monstrous. Sam dismisses Gwen’s warnings as folklore, until a simple accident unleashes a curse awakening a terror beneath the River Mersey.

With the fog thickening around the city and strange, winged creatures stalking the streets, Sam finds himself in a race against time to repair the seal and prevent an ancient being, the Watcher, from breaking free. But as the fog creeps ever closer and the Watcher’s minions grow bolder, Sam realizes that the only way to stop the rising terror is a ritual requiring blood, his own. Caught between the survival of Liverpool and his own life, Sam must face the unimaginable horrors lurking in the shadows. As the Watcher stirs and the city teeters on the brink of destruction, Sam is forced to confront an ancient evil and make the ultimate sacrifice in a desperate bid to save everything he holds dear.