Um casal da Filadélfia chora depois de uma tragédia indescritível que cria um rompimento no casamento e abre a porta para que uma força misteriosa entre na sua casa.

After a toxic spill creates an infectious outbreak, causing people to be filled with rage and turning to cannibalism, four survivors converge upon a house nestled deep in the woods. Together, they must try to survive the madness happening outside, the uncertainty and each other. As things become more grim, hope fades and supplies run low, people's true selves begin to show. The four must try to survive the monsters outside and within.