The Dark (2005)

"One of the living for one of the dead."

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.