In the future, the world's first neural-immersion sci-fi game, Starbound Endgame, launches. An ordinary girl named Huihui accidentally awakens anomalous privileges, allowing her to see the cracks where the game's underlying code overlaps with the real world. The identity of the mysterious player Yu'er is unknown; at times she's cold and distant, at others she's willing to risk her life to protect Huihui. As the game's instances continue to collapse, Huihui discovers that this so-called virtual world is actually a cage for the consciousness left behind by a lost civilization. Together, the two face interstellar battlefields, data abysses, and conspiracies in the real world, uncovering a truth that spans galaxies. Between code and heartbeats, they affirm the unique bond that ties them together.