Since the death of his wife 12 years ago, Victor Fielding has raised their daughter, Angela on his own. But when Angela and her friend Katherine disappear in the woods, only to return three days later with no memory of what happened to them, it unleashes a chain of events that will force Victor to confront the nadir of evil and, in his terror and desperation, seek out the only person alive who has witnessed anything like it before: Chris MacNeil.

A brilliant toy company roboticist uses artificial intelligence to develop M3GAN, a life-like doll programmed to emotionally bond with her newly orphaned niece. But when the doll’s programming works too well, she becomes overprotective of her new friend with terrifying results.