There was once a man who was summoned to another world, and saved it. Of course, he became too popular there, and turned into an isekai-normie. However, that man fell into a "trap" and was forcibly returned to his original world. Moreover, he had to start over as a baby! This is the story of the way-too-fantastic ex-hero who lived as a gloomy high-schooler, as he gets summoned once again to that same other world in a very unexpected development!

Tristan, the son of Meliodas and Elizabeth, inherits the power of the Goddess Clan and can heal people's wounds and injuries, but he often ends up hurting others due to his inability to control his Demon Clan power. To protect his family, Tristan heads to Edinburgh Castle and meets a host of new friends along the way.

The race to obtain the lost Ainu gold is nearing its peak, as even more formidable ex-prisoners are set on keeping their tattooed skins intact. Saichi "The Immortal" Sugimoto and Asirpa can finally move forward together, but Asirpa's time with Kiroranke and Ogata Hyakunosuke has slightly altered her ambition and strengthened her determination. As their party leaves the Russian territory, they gain a peculiar follower. Meanwhile, Toshizou Hijikata's crew makes major moves to get invaluable skins, falling into the poisonous trap of a dangerous convict. Although each group possesses a strong advantage over the others, even First Lieutenant Tokushirou Tsurumi—the most powerful and ruthless contender—cannot advance without Asirpa's help. However, his ominous plans for when they will inevitably meet remain a mystery.

The adventures of a whiny teenage Miyamoto Musashi, his electro-sword and demon-sealing revolvers, and his quest to win the love of the beautiful Kaguyahime.