College senior Leigh Swanson knew her friends' vacation to Montreal would become a drug-and-booze-filled road trip. Yet despite her best judgement, she gave into her roommate's pleas and hopped aboard the Canada-bound van.

It will prove to be the biggest mistake of her life.

On the road, Leigh and her friends meet Sam Tucker, a mysterious hitchhiker who is willing to exchange directions for a ride. Sam takes the gang on a shortcut—a detour through a dark Vermont forest. A deadly detour.

Among the many horrors that await Leigh and her friends is a fatal fungal disease, a grisly infection that has already claimed a number of victims. There is a cure—but Leigh is about to discover that sometimes, the only thing worse than sickness is: the Remedy.