Some storms can awaken the worst terrors. Where the sea gnaws at the cliffs, an older evil devours men.

Megan Howatt, 19, lives in Salwick, a village on the English coast that is slowly crumbling into the North Sea due to erosion. Torn between her desire to leave and her duty to her father, who has become an alcoholic and half-mad following the death of her mother, Megan can only rely on her friend Lou and her dog Kelpy, whom she rescued from the waves when he was just a puppy.

This village, threatened by both land and sea, becomes the ideal prey for a long-forgotten ancient entity that reappears one stormy night. It feeds on poor and divided communities. The villagers find their sheep slaughtered, and soon it is the humans’ turn to be torn apart by a mysterious evil that displays a terrifying malice in dividing the inhabitants of Salwick. Able to take on a most seductive human form before revealing its diabolical nature, this protean monster finds an unexpected adversary in Megan, who gradually realises that Kelpy, her docile but impressive mastiff, is also linked to ancient legends. Megan herself gradually feels herself imbued with strange powers that will bind her intimately to this land she wanted to leave at all costs, and which she will now defend at all costs.

Between modernity and the resurgence of the past, dark forces sow terror and anguish before confronting ancestral powers.