Torn (2010)

Samantha has lived her whole life in different foster homes. Now living in a small town, she never feels like she quite fits in, even with her own current foster family who might adopt her, or the boy who follows her around doing her classwork. So, it’s perhaps natural that she doesn’t know what to do with a curious tagalong little sister named Olivia. One day, Sam callously ditches Olivia, who wanders off into the woods on her own and disappears.

Sussie is 15, raised with her alcoholic mother and an absent father. She has lived in several foster homes. Now she gets one last chance with a new family, the Lindgren's who live in a large house by the sea.