Keira Knightley (King Arthur)
Thora Birch (American Beauty)
Desmond Harrington (Wrong Turn)
Daniel Brocklebank (The Hours)
Laurence Fox (Gosford Park)
Embeth Davidtz (Army of Darkness)
The film opens with the appearance of a dishevelled, blood-soaked Liz (Thora Birch), one of four private school pupils, also including Mike (Desmond Harrington), Geoff (Laurence Fox), and Frankie (Keira Knightley), who have been missing for 18 days. Liz is interviewed by a psychiatrist, Dr. Philippa Horwood (Embeth Davidtz), and describes what has happened to the four. Liz describes how she told Martyn (Daniel Brocklebank) about her unrequited love for Mike; Martyn promised to help, as he and Liz were best friends. Martyn took his four classmates, musician’s son Mike, his best friend Geoff, Liz and popular girl Frankie to an abandoned underground nuclear fallout shelter, where they decided to stay in order to avoid a school field trip. The four students climbed into the shelter, Mike reluctantly, and Martyn locked the door shut.
When Martyn was due to release them, the locked-in students belatedly realized they were trapped and began to turn on each other. Then they discovered that Martyn had hidden microphones in the shelter. Voice-acting, Frankie pretended to be sick, while Mike and Liz pretended to hate each other because Liz had said that this was what Martyn wanted – he had been in love with Liz “since we were eleven”. The plan apparently worked, as one morning they woke up and the hatch was open. They all climbed out, and Liz described how Mike hugged her, thanking her for saving them. However, soon after Liz finishes her story, the psychiatrist tells someone on the phone that she does not believe Liz’s story, while Liz waves happily to her from the window behind her.
Martyn has been taken into custody for questioning in regards to Liz’s story and the psychiatrist brings Liz back to her home. Martyn begins telling the police a completely different story, claiming that Liz and Frankie orchestrated the scheme, to allow Liz to get close to Mike, and Frankie to spend time with Geoff. The police are forced to release Martyn, despite their belief he is guilty, because they can find no evidence. In the meantime, Liz is experiencing flashbacks of the true events in the hole. Martyn comes to see her, angry and distraught that she has framed him. She runs from him through the garden and approaches a weir. Martyn cries, and Liz hysterically says that she knew they would let him go because they could not prove anything. She strokes his neck, but what happens next is not revealed.
At their next meeting, Liz tells the psychiatrist that she cannot remember what happened, however hard she tries. The psychiatrist is persuaded to take Liz back to the hole. Once inside, Liz reveals the truth: Liz had locked herself and her comrades in as a last-minute change to an adolescent plan to win Mike’s affection – a spontaneous response to the realization that both Geoff and Mike were attracted to Frankie and had both slept with her. Her obsession with Mike led Liz to believe that, with time, she could win him over, and that locking the door bought her time. Their sojourn in the bunker was initially meant to be a booze and drug party, but when they realized that they could not get out anymore, the mood quickly turned sour. Frankie soon ended up dead from side effects of her bulimia.
The remaining three gradually ran out of food and water. Before Liz can tell Mike that she had the key, Mike discovers that Geoff was hoarding Cola in his bag, and kills him in an uncontrollable outburst of violence by smashing his head against the concrete floor. Reduced to two, Liz suggested a suicide pact, whereupon Mike professed his love for Liz, prompting Liz to climb the ladder towards the shelter’s entrance and unlock the door. Perched on a landing high above the shelter’s floor, she told Mike she had had the key all along; she had done it all for him. Mike, overwhelmed by the events of the past few days, angrily rushed up the ladder towards her, but the ladder broke and Mike fell to his death, crushed by the broken ladder.
The film then cuts back to Liz and the psychiatrist, Liz concluding that since Mike is dead, he can never leave her. Dr. Horwood asks her to make an official statement which would corroborate Martyn’s version of events, although Liz refuses and it is revealed that Liz has murdered Martyn. The police then arrive at the bunker and Liz begins screaming for help as if the doctor was trying to hurt her. The body of Martyn is fished from the river where he had previously chased Liz and the key is found in his pocket, therefore placing guilt on Martyn and the police attribute his death to suicide. In the end, Liz is allowed to go free. The film ends with her sitting in the back of an ambulance, smiling at the doctor, which turns into a somewhat sinister look.The casting is superb. Every actor/actress suits his/her part exactly. The suspense is also particularly good at many points. On the whole, if you’re looking for a chilling look into the human psyche, this is a great film