On the furthest edge of the Outer Hebrides lies St. Budoc's Island, a remote community steeped in centuries-old superstition. Marine biologist John Calvary escaped the remote Scottish island he grew up on after a traumatic event. Now, thirty years later, John has been called back to St. Budoc's to investigate something from the depths of the Scottish seas that has washed up on its shore, something that is unearthing the island's devastating secrets and causing the islanders to quietly unravel. The corpse of an unknown, colossal sea creature.