As a last hurrah after college, friends Jeff, Karen, Paul, Mercy and Bert embark on a vacation deep into the mountains. With the top down and the music up, they drive to a remote cabin to enjoy their last days of decadence before entering the working world. Then somebody gets sick. Karen's skin starts to bubble and burn as something grows inside her, tunneling beneath her flesh. As they debate about how to save her, they look at one another and realize that any one of them could also have it. What began as a struggle against the disease soon turns into a battle against friends, as the fear of contagion drives them to turn on each other.