Shu hails from Datania, a sealed metropolis where children endure forced labor under the dominion of Zero, an artificial intelligence that enforces emotional suppression, erasing individuality to mold inhabitants into compliant drones. Driven by a yearning to explore beyond the dome and recurrent dreams of an unseen ocean, he engineers an escape with a group of fellow youths.

Their flight intersects with the Returners, insurgents battling Datania’s regime. Allying with them shifts Shu’s role from fugitive to rebel, thrusting him into direct clashes with Zero’s forces. His path unravels the mystery of DT, a rare substance embedded in select humans that Zero covets, positioning it as a linchpin in the struggle.

Seeking refuge in Amaroute, a sister dome-city, Shu uncovers its identical oppression, governed by Zero and defended by a clone of himself. This exposes the interconnected web of domes, engineered to build escape rockets for elites ahead of a catastrophic flood. Realizing external salvation is illusory, he pivots to dismantling the system from the inside.

In a final gambit, he converts Datania’s incomplete rocket into an ark to rescue citizens. Technical malfunctions stall the launch as floodwaters surge, leaving survival uncertain. The unresolved outcome cements his legacy as a spark for defiance, blending idealism with tactical ingenuity to challenge inevitability.

His evolution—from wide-eyed escapee to shrewd leader—is tempered by alliances with Ein, May, and Dolly, whose camaraderie fuels collective resistance, and by clashes with foes like Nines and Zero’s clones, testing his convictions. The arc confines itself to his metamorphosis within the core struggle, charting a course through disillusionment, revelation, and tenacious rebellion.