The world feels alive because it's built on a lie everyone has already accepted. Sakura stumbles into the machinery keeping that lie running, and the show doesn't let her pretend ignorance is safer than the truth. A girl who sings in secret discovers the song itself is the problem.
Sakura lives a double life aboard a sprawling space colony fleet designed to mirror Earth's cities. By day she's an unremarkable middle school student on a provincial satellite ship. By night she sings in an online duo with Eve, pouring her real emotions into music that nobody knows comes from her. When a resistance movement erupts on the fleet's master ships, the conflict centers on one thing: control of Tiamat, the AI system that governs everything. A crucial key to accessing it vanished eighty years ago, but rumors suggest it's resurfaced. Now both the government forces and the rebels are hunting for it, and Sakura's world starts collapsing when her secret music career gets tangled up in the search. What begins as a personal struggle to keep her two identities separate becomes a race to understand what Tiamat really is and what freedom actually means aboard a ship where the sky itself is artificial. The truth ties together music, revolution, and the future of everyone aboard.