The world of Lingalind is surrounded by a mystical wall with seemingly nothing beyond its confines. Worshipped as the mother of the land, the wall delivers celestial gift capsules called "Rakuho'' to locations across the continent. Arriving once a month, the capsules contain metallic armbands that allow the wearer to transform into a mechanical being known as a "Briheight." As a result, Lingalind is thrown into constant turmoil by its warring nations, all hoping to strengthen their military prowess by procuring the offerings for themselves. One day, a Rakuho crash-lands in the countryside with an unexpected inhabitant—a mysterious black-haired man. All eyes are set on this strange newcomer, who calls himself "Back Arrow," when he claims to have hailed from a place beyond the wall—a revelation that can potentially unravel Lingalind's entire dogmatic foundation. [Written by MAL Rewrite]

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.

Recap of the first seven episodes of 91 Days series.

On the surface, the thought of Kyouko Hori and Izumi Miyamura getting along would be the last thing in people's minds. After all, Hori has a perfect combination of beauty and brains, while Miyamura appears meek and distant to his fellow classmates. However, a fateful meeting between the two lays both of their hidden selves bare. Even though she is popular at school, Hori has little time to socialize with her friends due to housework. On the other hand, Miyamura lives under the noses of his peers, his body bearing secret tattoos and piercings that make him look like a gentle delinquent. Having opposite personalities yet sharing odd similarities, the two quickly become friends and often spend time together in Hori's home. As they both emerge from their shells, they share with each other a side of themselves concealed from the outside world. [Written by MAL Rewrite]