Set in the year 2100, the world is connected by a computer network. Children around the globe become Web Divers, converting their consciousnesses into data, and enjoy playing together in the cyber park known as Magical Gate. However, a mysterious computer virus emerges, starting to destroy Magical Gate from the inside out. In cyberspace, programs called Web Knights were created to protect the children. But the computer virus has turned all the Web Knights against the children. The only Web Knight to escape the "brainwashing" is Gladion. Gladion seeks the help of Kaito Yuki, a fourth-grade Web Diver.