In the world of Digimon Beatbreak, Tomorou Tenma possesses an exceptionally powerful e-Pulse, the energy generated by human emotions and thoughts that powers Sapotama devices, egg-shaped AIs used in daily life. However, his strong e-Pulse often causes malfunctions in these devices. One evening, a mysterious Digimon named Gekkoumon emerges from his Sapotama, declaring its intent to consume Tomorou’s e-Pulse.
Gekkoumon is a being that thrives on e-Pulse, arising due to errors in Sapotama systems. Some Digimon extract all energy from humans, leading to a condition called Cold Heart that leaves victims in a coma-like state. After Tomorou's older sibling, Asuka, falls to this fate, he vows revenge.
When Tomorou meets Glowing Dawn, a team of Digimon users who track down dangerous Digimon for rewards, their leader, Kyou Sawashiro, hints at the possibility of reversing Asuka's condition. Despite initial reluctance to trust these newcomers, Tomorou decides to join forces with them, recognizing that rescuing his brother may require more than he can achieve alone.