A young soccer player's ordinary life changes when hidden powers awaken in him as he saves someone on the field. Invited by his senior Xia Zhi, Gu Tian rides Subway Line 36 to Tianguan Academy, a school the Heavenly Great Sage founded to hold back invasions from other worlds. New students arrive every year, yet in the end only nine of them become official Heavenly Officers. The academy offers the finest teachers alongside strict assessments and a brutal elimination system that pushes everyone to the limit. With some luck, Gu Tian becomes the 81st student to clear the entrance trial. Guided by celestial masters, he studies spells and divine decrees, sharpens his fighting skills against strong rivals, and works toward joining the Nines in this action fantasy ONA.