Yūichi Kannami, a genetically engineered Kildren trapped in perpetual adolescence, serves as a fighter pilot in orchestrated corporate wars. Stationed at Area 262 as the replacement for the vanished Jinroh Kurita, his past remains shrouded in amnesia, though his unmatched combat skills betray lingering instincts from former lives.

Arriving at the base, fragmented memories resurface through encounters with his commander, Suito Kusanagi, who recognizes his idiosyncrasies—like snapping matchsticks after lighting cigarettes—a ritual echoing his cyclical existence. Investigations unravel Kusanagi’s role in Jinroh’s death, a mercy killing he requested, intertwining her grief as a fellow Kildren and mother to a daughter out-aging her.

Connections with others deepen his existential unease: civilian mechanic Fuuko observes his eerie resemblance to Jinroh, hinting at a past romance between Jinroh and Kusanagi. Fellow pilot Midori Mitsuya confronts him with suspicions of implanted memories, propelling him to embrace his identity as Jinroh’s reborn iteration. This acceptance leads to a climactic duel against "The Teacher," an adult ace pilot implied as his genetic originator. His defeat perpetuates the Kildren cycle, underscored by the arrival of Isamu Hiragi, a new pilot mirroring his voice and mannerisms in a post-credits vignette.

Defying resignation to fate, Yūichi challenges Kusanagi’s despair, urging her to seek change rather than perpetuate cycles. His final, defiant clash with The Teacher—a conscious embrace of predetermined loss—hints at subtle shifts in Kusanagi’s resolve, reflected in her guarded warmth toward Hiragi.

Rootless and ageless, Yūichi’s identity coalesces through fractured memories and environmental echoes. His struggle against existential entrapment and yearning to transcend engineered purpose underscore a narrative of repetition and fragile hope, where actions ripple faintly against an immutable system.