On their way back home during the spring break, Darry and Patricia Jenner witness a mysterious person dumping something down a tunnel. Deciding to discover what was dumped down there, Darry discovers a huge disturbing hideout full of modified bodies. Darry and Patricia set off to get help, unaware that the individual is now aware of who has been down the tunnel. Darry and Patricia soon realizes that their pursuer is not just a mysterious person, but something even more horrifying, who has more in store than they could possibly imagine.