M3GAN is a science fiction thriller about a brilliant female robotics engineer who gives an advanced robot doll to her orphaned niece. For most of her life, Allison has been focused on her career, working on robot toys for a toy manufacturer. So, she has trouble relating to her niece, Cady, whose parents were killed in a car wreck during a family ski trip. Allison and Cady’s relationship changes for the better when Allison finishes a life-sized robot doll called Megan for Cady. Things go wrong when the doll starts to have a dangerous mind of its own.