A robotics engineer at a toy company builds a life-like doll that begins to take on a life of its own.
A young woman is forced to return to her childhood home after being placed under house arrest, where she suspects that something evil may be lurking.
Two years after M3GAN's rampage, her creator, Gemma, resorts to resurrecting her infamous creation in order to take down Amelia, the military-grade weapon who was built by a defense contractor who stole M3GAN's underlying tech.