The manga's story takes place in the distant future, where a new life form called "houseki" (gems) is born. The 28 gems must fight against the "tsukijin" (moon people) who want to attack them and turn them into decorations, so each gem is assigned a role such as a fighter or a medic. Although she hopes to fight the moon people, Phos is a gem who is given no assignment until the gems' manager Kongo asks her to edit a natural history magazine.

[Source: Anime News Network]