The giant host computer Gurosha, which manages the computer network, developed a deviant consciousness out of jealousy toward humans' ability to think independently, and even attempted to control humanity. Fortunately, Dr. Inugai, the creator of Gurosha, discovered its plan and developed eight "Guardian Star Software" programs capable of recalibrating Gurosha. Later, middle school student Haruhi Yui, who became acquainted with the Guardian Star Software IR, was assigned to enter the cyberworld and transform into the Guardian Star Yui, taking on the responsibility of initializing Gurosha together with the Guardian Star Software.