In 1999, Earth faced a crisis as the planet Lar Metal approached. Yukino Yayoi, a junior‑high school teacher with a deep interest in astronomy, learned about the incoming planet from Dr. Amamori of the Tokyo Observatory, who valued her knowledge. In reality, Yayoi is Queen Millennia, having arrived from Lar Metal a thousand years earlier and observing humanity ever since. When a shower of meteors begins to fall, panic erupts across the globe. Amid the chaos, Yayoi’s student Hajime steps forward to help. She invites him into a vast underground cave to seek safety and uncover what lies beneath.