Summer Forrest is reborn seven days before an apocalyptic deep freeze, remembering her past death. She stockpiles goods with husband Ethan Clark, converting a semi-truck into a mobile fortress, hiding in an underground bunker. After the deep freeze, her family, neighbors, and gangs try to force her to hand over supplies with blackmail and violence. Summer and Ethan fight them off, expanding their survival system. In a collapsed, frozen world, they live in their warm fortress.