In an attempt to pull her family together, Adèlle travels with her young daughter Sarah to Wales to visit her father. The morning after they arrive, Sarah mysteriously vanishes in the ocean. Not long after, a little girl bearing a striking resemblance to their missing daughter reveals that she has retuned from the dead — and that Sarah has been taken to the Welsh underworld.
Chloe, a divorced schoolteacher, falls in love with educational psychologist Dan, only to be left heartbroken when the police arrest Dan on suspicion of sexually abusing a six-year-old that he has been assessing. Chloe is forced to confront the possibility that Dan may have also sexually abused her two daughters, Alice and Lucy.
