The background of SAS story is adapted from 1980 Iranian embassy hostage incident. As the first sharp knife of the British army, SAS is equipped with a series of equipment suitable for CQB (indoor close combat) in the film to fight against hostage takers. At that time, the United States sent officials to jointly develop nuclear weapons with Britain, but this was strongly opposed by radicals, and a large-scale demonstration was held, with the slogan "Nuclear weapons cannot bring peace". However, this did not achieve their goal. The secret group headed by Francci planned the kidnapping of American tourists and asked the government to agree to their demands. In order to ensure the safety of the hostages, the British government sent captain Skullen, a SAS special force, to infiltrate the kidnapping group. From then on, mysterious and cruel espionage began ... In order to rescue the hostages, the government dispatched all the personnel of SAS special forces, and fierce fighting began. ...