Six meteors devastated the world. Six moons now orbit the sparse land. Surrounded by the ocean, a handful of gemstones in human form fight for their survival—hunted by the vile inhabitants of the moons, who want to turn their bodies into jewelry. Phosphophyllite, better known as Phos, is a young gemstone who dreams of helping his friends in the battle against the Lunarians. However, Phos is fragile and not suited for combat, and instead is tasked with creating an encyclopedia about the nature and history of the world. In search of entries for his work, he encounters Cinnabar, a toxic gemstone who keeps a lonely watch over the land at night. Soon, the two friends find themselves entangled in the chaos of an ancient war.