In a world inhabited by crystalline lifeforms called The Lustrous, every unique gem must fight for their way of life against the threat of lunarians who would turn them into decorations. Phosphophyllite, the most fragile and brittle of gems, longs to join the battle. When Phos is instead assigned to complete a natural history of their world, it sounds like a dull and pointless task. But this new job brings Phos into contact with Cinnabar, a gem forced...

Now with new legs, Phosphophyllite is ready to go to battle. But when that new strength is needed the most, Phos is too scared to use it. Mortified by this failure, Phos undertakes the self-imposed punishment of staying awake all winter while the other gems sleep. But winter has its own share of dangers ...