Takamine Kiyomaro, a disheartened indifferent man, unexpectedly receives a tiny demon called Gash Bell to care for. Unaware that Gash is caught in a fierce contest to determine the demon realm"s sovereign, he soon learns each demon must choose an earthly master and clash with rivals until only one remains. Naturally, Kiyomaro becomes Gash"s mentor, and as they fight together, he discovers the value of friendship and bravery. Despite his initial apathy, Kiyomaro's perspective shifts dramatically as the battles intensify and growth.