 ZERO HOUR is a unique documentary format - a ticking clock hour of television which transports the viewer into the gripping countdown to some of the most dramatic events in recent history. Terror in Tokyo tells of the attack on 20 March 1995 on the Tokyo Subway using Sarin gas. In the attack members of the Aum Shinrikyo (Supreme Truth) cult carried six packages onto Tokyo subway trains and punctured the packages with umbrella tips, releasing deadly Sarin gas killing 12 persons and injuring more than 5,000. It was a planned and co-ordinated attack. Asahara, the leader of Aum had been tipped off about planned police raids on cult facilities by an insider, and ordered the attack in central Tokyo to divert attention away from the group. The plan backfired, and the police conducted huge simultaneous raids on cult compounds across the country. Over the next week, the full scale of Aum s activities was revealed for the first time. At the cult s headquarters on the foot of Mount Fuji, police found explosives, chemical weapons and biological warfare agents, such as anthrax and Ebola cultures, and a Russian MIL Mi-17 military helicopter. There were stockpiles of chemicals which could be used for producing enough sarin to kill four million people. Police also found laboratories to manufacture drugs such as LSD, methamphetamines, and a crude form of truth serum, a safe containing millions of dollars worth in cash and gold, and cells, many still containing prisoners.