Born in a quiet valley. Raised by discipline. She rose to become the supreme master of martial arts

 A girl who grew up in a valley,

A distant valley surrounded by mountains — where the underworld still exists.

In that valley, a girl was born — Arin. Her parents were martial arts masters who went into hiding after a terrible war.Arin was "silent" since childhood.

He spoke little, but his eyes had a strange determination.Every morning he would run in the mountains with his father. His mother would teach him meditation, concentration, and body control.At the bottom of the mountain was an old dojo (training hall).

There, Arin practiced alone every day.

Sometimes with a stick, sometimes with his bare hands, and sometimes Suddenly one day, a group of outsiders arrive in the valley.

They say, “Your father’s name was Shinmei. He was the last Grandmaster.”

They want Arin to return with them, because a secret organization (The Crimson Fist) wants to take over the world, and they are the only ones who know the forbidden techniques of martial arts.