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.

When Kylie Bucknell is sentenced to home detention, she’s forced to come to terms with her unsociable behaviour, her blabbering mother and a hostile spirit who seems less than happy about the new living arrangement.