Qi Yu was an ordinary boy with "one rune" who both went to school and worked to support his little sister. His life was difficult, but he's still optimistic.

One day, he was attacked by a monster and was saved by a mysterious girl. At the critical moment, the "rune" on Qi Yu's forehead turned into a vertical eye, resonating with the girl's "rune." He was able to utilize her power, enhance it and defeat the monster.

After that battle, Qi Yu's life completely changed with his new mysterious power and companions.