Iota

It's Christmas time on the Scottish coast. April, a girl of about six or seven wakes up, calls to her twin who continues to sleep, gets up and runs outside. A year later, the girls' father sits at the kitchen table, staring; Samantha, the daughter who had been sleeping, comes downstairs. She's mute and signs to her father; they go down to the beach. That night, dad finds a long strand of hair and, after Sam falls asleep, dad hears her voice calling to him. Is a Christmas reunion at hand? - IMDb