Something follows the Conover family as they drive from L.A. to Chicago. Nine year old Michael sees a face form in the window of the family car. Fourteen year old Alison sees two creepy children at a motel. A car stays behind them on the road, never passing or falling behind. Wherever the Conovers go, wherever they look, they see a large woman and her children. Patiently, relentlessly, the woman gets closer.
She is superhumanly strong. She can enter and leave a locked room at will. Confused and scared, the Conovers can't understand what is happening. Everywhere they turn they see death coming for them. Mama teaches her children, like a lioness teaches her cubs to hunt. The Conovers realize that they are the prey.