She is programmed for friendship: M3GAN is no ordinary toy, designed to be a child's best friend and a parent's ally. When robotics expert Gemma (Allison Williams) unexpectedly becomes the guardian of her orphaned niece, she takes the prototype of the high-tech doll home with her. A momentous decision, because M3GAN develops an almost murderous protective instinct. Not even in her wildest dreams did Gemma expect a doll to take its task so seriously when she gives it to her niece. After all, she works for a toy company and has programmed the lifelike doll herself. But M3GAN, equipped with artificial intelligence, takes her job as best friend deadly seriously.