Modern thriller based on the best-selling cult novel by Guy Burt. School nerd Martyn (Daniel Brocklebank) helps four school friends, Liz (Thora Birch), Mike (Desmond Harrington), Geoff (Laurence Fox) and Frankie (Keira Knightley) avoid a school field trip to Wales by taking them to an old underground bunker. Together the teenagers party non-stop for three days in their sound-proof shelter, but when Martyn doesn't return to let them out, the party atmosphere changes quickly into a living nightmare. Liz is found a few days later walking towards the school, covered in blood and traumatised. She is taken to a police psychologist where she tells her story; but when Martyn is later picked up, he gives a very different account.