Sue Ann (Oscar winner Octavia Spencer) is a loner who keeps to herself in her quiet Ohio town. When she is asked by a teenager to buy some booze for her group of friends, Sue Ann offers the basement of her home for the kids to hang out and party. But there are some house rules: Someone has to stay sober. Don't curse. Never go upstairs. And call her "Ma". As her hospitality starts to curdle into obsession, what began as a teenage dream turns into a terrorizing nightmare, and Ma's place goes from the best place in town to the worst place on earth.