M3GAN is a marvel of artificial intelligence, a lifelike doll programmed to be the best companion for children and parents. Designed by Gemma, a brilliant robotics engineer, M3GAN can listen, watch and learn as it acts as friend and teacher, companion and protector for the whole family. When Gemma becomes the reluctant caretaker of her 8-year-old niece, she decides to give her a prototype of M3GAN, a decision that leads to a result beyond her wildest expectations.