Taiyō Tsukuba is a 14-year-old junior UN2.1 official serving as a white-hat hacker who monitors and thwarts illegal digital activities. He operates with a personal surveillance drone named Bright. Externally polite and softly respectful toward others, he harbors an intense internal drive for justice that surfaces fiercely when confronting wrongdoing.

His journey to the commercial space station Anshin occurs through Deegle's sponsored underage space experience campaign. Aboard Anshin, he joins Touya Sagami and others in a group effort to confront a crisis, collaborating with colleagues originally tied to Jet and the world airport.

Taiyō possesses ear-length brown hair and green eyes, embodying the hacker archetype through his technical expertise in digital security enforcement. His narrative centers on ideological opposition to Touya Sagami, another young hacker. This conflict forms a light/darkness dichotomy: Taiyō enforces mandated AI intelligence limiters for the UN, while Touya advocates for their removal. Their drones—Bright (white) and Darkness Killer, or Dakky (black)—visually reinforce this contrast.

A comet-triggered crisis traps Taiyō with Touya aboard Anshin despite their clashing views. Forced cooperation becomes essential for survival amid station failures like decompression, failing life support, and external threats, potentially evolving their adversarial dynamic.