After war laid waste to the world, humanity rebuilt its civilization around the "Other Realm", a depression formed on the surface, relying on Pathfinders bound to contracted exotic beasts to hold the line of survival. Kai Vale, an eighteen-year-old boy from the Contaminated Zone, enters the Pathfinder Preparatory Camp to treat his father Tom, who suffers from radiation sickness, and fund his sister Mia’s schooling. Yet he is publicly humiliated by an apprentice from the Oasis Zone. To retrieve the Summoning Fruit his father bought with a lifetime’s savings, he leaps into a garbage heap to form a contract, gaining an unremarkable little black snake. Everyone writes it off as a worthless exotic beast, only for a serpent-eye omen to appear across the heavens and earth, hinting at a truth no one knows. Julian, an elite from the preparatory camp, monopolizes resources with his T2 Nemean Lion. Teaming up with David, District Chief Damian and Instructor Nix, he strips Kai of his testing rights, using frame-ups and humiliation to break him; Lucy also hesitates and misses her chance to stand with him. Desperate to save his father, Kai ventures into the Mist-Tide Forest. Guided by Sophia, he reaches the heart of the Other Realm, where the little black snake awakens as Jörmungandr, the sole T0 exotic beast. He then returns to the Federal Apprentice Grand Tournament with his stolen dignity. Through strength, evidence and resolve, he exposes the discrimination against residents of the Contaminated Zone and corrupt protection by those in power, revealing himself to all as the true prodigy, and forging a new life for his family.
