In the aftermath of a global cataclysm, harbor authorities have reactivated an ancient lighthouse on a forsaken island to keep the surrounding seas navigable amid spreading chaos. A lone keeper is dispatched to man the beacon. He is the only thing standing between passing vessels and the dark. His family waits for him far away. Each night on duty grows stranger than the last — mariners report encounters with creatures that should not exist, ships drift back from deep water with no one aboard, and the fishing village on the island performs rituals to call back the dead. Whether the keeper will preserve his sanity and protect those who depend on him — or be lost to whatever is gathering beneath the surface — remains to be seen.