Sue Ann (Octavia Spencer) is a lonely veterinary aide who lives in a town in Ohio. Things start to go wrong when she meets a group of teenagers. Despite their age differences, Sue Ann was invited into the clique, which she buys alcohol for. At first, it was fun for Sue Ann, who came to be called Ma, as her friendship with the high schoolers gives her the opportunity to be social and it gets her invites to parties. However, it becomes increasingly difficult for her to let go of her friends during weekends. She eventually develops an obsessive fixation on the group. The involvement of her friends' parents also triggered past trauma. These developments lead to violence.
