Awakened into a world where humanity has been petrified, scientific genius Senku and his brawny friend Taiju use their skills to rebuild civilization.

As the world moves on from the war and technological advances bring changes to her life, Violet still hopes to see her lost commanding officer again.

A long time ago, there was a valiant swordsman who came to be known simply as "the hero." There was a demon who has caused people suffering. The hero and his companions arrived to challenge the demon to a battle and by combining their powers, the battle was brought swift conclusion. With no one around to cause trouble, the island became a quiet place where everyone could live together in peace. Several years later, the demon is revived. Our present-day protagonist, Dai, lives on a remote island in the southern seas and dreams of becoming a great hero. When he hears about the demon's revival, Dai and his friends take it upon themselves to stop him and the evil force that revived him. Along the way, Dai discovers the identity of "the hero," the truth behind the evil force who revived the demon, and Dai's own hidden powers that surface in times of peril.

People lived in peace without knowing who the true heroes were during the devastating battle against Majin Buu. The powerful Dragon Balls have prevented any permanent damage, and our heroes also continue to live a normal life. In the far reaches of the universe, however, a powerful being awakens early from his slumber, curious about a prophecy of his defeat.