United Kingdom: April 20 2001
Ranking: 3,811 out of 16,012 movies (up 1806)
When Liz Dunn and three of her prep school friends decide to bail on their scheduled weekend field trip and hide in a long-abandoned bomb shelter, they expect to party and hang out. They don't expect someone to lock them in. As anxious hours turn into desperate days, fear and insecurity erupt uncontrollably as their spontaneous adventure turns into a bloody fight for survival.