故事发生在遥远的未来世界之中,地球上存在一种身体由宝石形成的宝石人形生命体,这种生命体自打一出现以来就经历着遭人掠夺的悲惨命运,如今,全世界仅剩下28人。来历不明的神秘种族“月人”出现开始掠夺宝石人,将他们残忍的制作成装饰品,不仅如此,甚至将他们加工成为武器。 十分易碎又没有韧性的磷叶石(黑泽朋世 配音)、能够释放出银色毒液的辰砂(小松未可子 配音)、向往浪漫爱情故事的钻石(茅野爱衣 配音)、潜心于战斗的圆粒金刚石(佐仓绫音 配音)、个性活泼开朗的摩根石(田村睦心 配音),为了抵抗月人的入侵,世界上仅存的宝石人们决定联手。In the distant future, a new immortal and genderless life form called Gems populate the Earth. The 28 Gems must fight against the Lunarians, who attack them regularly to abduct them and to turn them into decorations. Each Gem is assigned a role, such as a fighter or a medic. Being only 300 years old, Phosphophyllite is the youngest of the Gems and has no assignment yet. They want to help to fight the Moon Dwellers, but are too weak and brittle for battle. One day the master of Gems, Kongou (Adamantine), assigns them the task of creating a natural history encyclopedia.