Three friends, Naoto, Yuuka, and Ippei have put together their own Personal Computer. The same day that the trio makes this computer, their classmate Takeshi Todo, a lonely rich boy who loves playing monster-creating PC Games, is met by the evil Kahn Digifer, a psychotic being living within the "Computer World." Kahn Digifer begins to work with Takeshi to bring Takeshi's monsters into the Computer world and wreak havoc, first by attacking a hospital's computer system, putting the lives of all of its patients in danger. One of these patients is Naoto's brother, Shou. Racing home, Naoto and his friends try to destroy the monster on their own with vaccines, but have no luck. Suddenly, Naoto is sent a mysterious changing brace from the computer, and meets a mysterious "policeman" of the 'Hyper World' known as Denkou Choujin: Gridman. Gridman has been tracking down Kahn Digifer, but is unable to fight without having a solid form to fight with. Naota uses the brace to merge with Gridman in the computer, allowing Gridman to fight and stop the monster. But this is not the end of Kahn Digifer's attacks, now our hero's must stop Takeshi AND Kahn Digifer with the help of Gridman and his "Helper Programs!"