After numerous tryouts (selection tests), rookie Gray finally becomes a "hero" as part of HELIOS' 13th generation. After being assigned to the East Sector, he spends his days receiving extremely strict instruction from his mentor, Asch. Despite encouragement from fellow rookie Billy and his mentor, Jay, Gray is beginning to lose confidence in himself as a "hero." Meanwhile, the chaos caused by Eclipse is becoming increasingly extreme. Furthermore, the increasing number of Zeros is putting HELIO...