On the planet Gift, blue crystals called giftium are mined from deep underground, and in the boomtown of Garden Indigo a boy named Sogo Amagi collects the rarest specimens as a hobby. When his classmate Kaon bolts from an arranged engagement, the chase pitches the two of them into a cave system, where they find a red-eyed, blue-haired girl named Felia sealed in crystal. With friends Roman and Otto, Sogo takes Felia in as armed forces begin hunting her.