A massive central network called Comnet links the computers of the world, forming a single global computer system. Comnet, designed to serve the interests of mankind, is managed by the supercomputer, Grosser. However when Grosser decides to take over the world, a savior is needed! A computer-illiterate girl named Yui Kasuga inadvertently makes contact with the software program IR, one of the eight 'Corrector' programs scattered through the cyber world of Comnet. IR which recruits her as savior of Comnet and pulls her into the virtual world inside. There, Yui is given the power to become Corrector Yui so that she can fight against Grosser and his four hench-programs - Virus, Jaggy, Freeze, and War Wolf. Yui repeatedly travels into cyberspace to defeat Grosser's schemes, which range from turning e-mail messages into strings of insults to altering the advice from an online romance advisor.