Tomorou Tenma possesses a uniquely strong e-Pulse—the energy created by human thoughts and emotions that powers egg-shaped AI devices named Sapotama. The world's everyday life relies on the assistance of Sapotamas, but the force of Tomorou's e-Pulse often causes glitches in them. One night, a strange creature calling itself Gekkoumon emerges from his device and insists on eating Tomorou's e-Pulse. Gekkoumon is a Digimon, a creature feeding on e-Pulse that was born from an error in Sapotamas. Some Digimon completely drain humans of their energy, leaving them in a comatose state known as Cold Heart. When Tomorou's older brother, Asuka, becomes a victim of this phenomenon, Tomorou vows to avenge him. Tomorou meets a group of Digimon-wielders called Glowing Dawn, who hunt down rogue Digimon