Oh please wise ones help me as this is so annoying 
I think it was a tv drama or possibly a film, may have been based on a true story?
It was a military family, and I think 2 daughters, they went to school and lived on a military base but I think the school wasn't on the base, it was based abroad, and I think there was snow on the ground? One girl got kidnapped and was locked up in the woods, she managed to escape one day and was found and when she returned home, they were convinced it wasn't her?
I really can't remember the name of it and I know that's a vague description but I just can't remember what it's called!