A tense and claustrophobic thriller emerges when twelve people become trapped in a London Underground train carriage. The fear of being trapped underground with very little air and apparently no rescue service underway becomes very real as we witness the initial panic and fear experienced by the passengers. As the temperature rises and tempers fray, an electrical shortage on the train shrouds a brutal murder and when the lights eventually come up we are faced with a new and more chilling revelation - there is a murderer aboard and nowhere to run.〔(''Underground'' )〕