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.

A deep sea submersible pilot revisits his past fears in the Mariana Trench, and accidentally unleashes the seventy foot ancestor of the Great White Shark believed to be extinct.