Reeling from the loss of her mother and father, teenage Maryann (Natasha Calis) moves in with her grandparents, and is grateful when she manages to befriend Andy (Charlie Tahan), a boy who uses a wheelchair. As Andy is very sick he must stay within his home per the instructions of his mother, Katherine (Samantha Morton), who also forbids him from having any visitors. When their visits are discovered, Andy's father, Richard (Michael Shannon), is initially fine with the visits, but Katherine is having none of it and her behavior grows increasingly erratic.