Tomorou Tenma possesses a unique power called "e-Pulse"—energy derived from human emotions that powers AI devices called "Sapotama." Today's world relies entirely on these devices, but Tomorou's energy is so high that it often causes them to malfunction. One night, a strange creature named Gekkoumon emerges from his device, which is actually a "Digimon" and wants to feed on Tomorou's energy. These Digimon are actually created by the AI ​​devices' errors. Some dangerous Digimon drain people's energy, leaving them in a comatose state called "Cold Heart." When Tomorou's older brother, Asuka, falls victim to this, Tomorou decides to take revenge. He meets a group called "Glowing Dawn" who hunt these stray Digimon. Their leader, Kyo, reveals that Asuka can be cured. Now, Tomorou must reluctantly side with these strangers to save his brother.