The film tells the story of two good friends who live together, Andrew, an agoraphobic travel agent who works from his home, and Dave, a loser who works in an office where he is treated with contempt. Just when it seems things can't get any worse for the two, the entire world outside of their house disappears and is replaced with an endless white void.

After hearing a child screaming for help from the green depths of a vast field of tall grass, Becky, a pregnant woman, and Cal, her brother, park their car near a mysterious abandoned church and enter the field, discovering that they are not alone and, for some reason, they are unable to escape a completely inextricable vegetable labyrinth.