High school student Ryugo Arumi, on the verge of abandoning the karate he's dedicated himself to for years, spends his days in a state of apathy.

One early summer evening, Ryugo resolves to invite his childhood friend, from whom he'd grown somewhat distant, to a summer festival.

Just as he finished sending a message on his mobile phone and looked up, the surrounding scenery had transformed into an unfamiliar grassland――.

The place he had wandered into was a fantasy world brimming with swords, magic, and monsters.

Encounters with various people, battles against various enemies.

Ryugo carves his way through this harsh otherworld, where swords and magic clash, using his bare fists.

Without ever knowing why he was summoned to that world.

――A modern Japanese boy who stakes everything on his fists, and a proud young female knight from another world.

The story of two individuals whose encounter is surely unforgivable.