The plot revolves around a group of adventurers named Hamel, Flute, Raiel, Trom, and Sizer, who embark on a journey to the demon continent, seeking to avert a catastrophic event.

This led to a period of prosperity and peace for humanity, resulting in the founding of cities and nations, as well as the development of science and magic.

The demons fled north, establishing their capital city of Hameln on the northernmost continent, and a never-ending war broke out between humans and Mazoku for survival.

Pandora's children, one raised among humans and hated by all, and the other living with the Mazoku without ever feeling any affection, are destined to reunite and put an end to the war, one way or another.

After saving the remote village of Staccato from nearby demons, he decides to kidnap an orphan girl named Flute as payment for his services.

Along the way, they meet Raiel, the hero of love and Hamel's childhood friend, who plays beautiful and powerful melodies with a 500 kg golden piano that can summon spirits and manipulate people.

After his land is burned and his parents are murdered before his eyes, the young prince vows revenge and joins the group on their quest north.

Reunited with her estranged mother, Flute tries to deal with pent-up emotions while Hamel is sent to find a man who can repair his magical violin.

The battle ends with the victory of Sforzando and the revelation that the Queen had only a few years to live since her barrier magic makes the user pay by giving up his lifespan.

Two years after the abrupt end of the sequel manga, Watanabe created a sort of version of the original series in an alternate universe.