6 cats who are apprentices ran away from their clans because of the warrior code, they then travel to WindClan and to MotherMouth finding the ancient MoonStone. Rainbow'Paw has once been there as a young Kit, but doesn't remember much from it. So the six apprentices decide they will live at the MoonStone until they're old enough, but hearing how cats and dogs hurt the MoonStone from times, so the apprentices decided that it is now their duty to become the guardians/protectors of the MoonStone and protect it until their death (Carrying on the prophecy Of-course) this is when a new clan is formed named MoonClan.