London is under attack. People are dead. Many more lives hang in the balance as a group of highly trained gunmen storm the historic Lanchester Hotel on Park Lane. The gunmen have given the government just five hours to meet their demands before they blow up the building. Shots ring out. Some guests panic. Others text their loved ones. Still more try to escape. All are united by one thing: fear for their lives. All -- except one man who has information so dangerous that it must be kept safe -- at any price. Darkness falls. The gunmen become increasingly violent. One question is in everybody's minds. Will they survive the night?