Horror film where couple find a girl, who is unable to talk [closed]

I'm looking to see if anyone can identify this movie. It's about 6 years + old. A couple live in a house near the sea and white cliffs. The couple find a girl, clearly shook up and unable to speak. They take her to the doctor, who makes a diagnosis that she had her skull forcefully open. (something about her parents opening her skull to let the evil out).

There is a scene in the movie where a mass cow/people suicide takes place off the white cliffs.

The movie ends with the girl drowning, and the woman trying to help her out. She fails however, and is seen falling in to the water with the girl.
The end of the movie is quite difficult, and ends with the woman being locked out of her body, and the spirit of the girl being inside her. They all go to the house, where the husband shuts the door and the spirit of the woman is locked outside.

At the very end, the now possessed woman opens some sort of lock-box with a hidden key, and takes out some pictures.

identify-this-movie horror

Best Answer

It sounds like The Dark, (2005).

When Ebrill, who was a sickly child, died, her father gave her to the ocean, sending her to Annwyn. He then convinced his followers to throw themselves into the ocean, claiming that it was the way to Paradise, while he privately hoped that their sacrifice would return Ebrill to him from Annwyn. Ebrill did come back, but, something came back with her. Her father tried to draw the evil out of her, through trepanning and locking her in her room.

The ending is described in the IMDB Q&A:

So Sarah is back alive. Adele thinks she is back too, but as you can see James completely ignores her, he actualy slams the door shut right in frot of her, and she can't get it open. Then James tells Sarah that Adele sacreficed herself to save Sarah.