Seventeen-year-old Loretta Lynn Duvall has spent her life cleaning up her mother's messes. When her mom leaves on a summer business trip, Loretta and her friend Cora get stuck working at Willow Grove, the house and property owned by crazy old Noleen Deerborne.Meanwhile, Loretta's friend Ethan has grown suspicious of his parents' involvement in a survivalist organization called The Group. What's more, Ethan suspects that a connection between Willow Grove and The Group lies in an underground maze of tunnels dating back to the Civil War. After a series of suspicious incidents, these inquisitive teens decide to investigate further. Soon Loretta and her friends have tunneled themselves into a mess of their own.