In the year 2005, a race of alien monsters called Zonders emerge from underground and launch a series of attacks on the city of Tokyo. The only defense against these creatures is the secret agency known as the Gutsy Geoid Guard (or 3G) and their ultimate weapon, the awesome giant robot GaoGaiGar. GaoGaiGar's pilot, Guy Shishio, is a former astronaut who was nearly killed two years before when the Zonders first crashed to earth. (myanimelist.net)