Pokémon: Clefairy and the Moon Stone

At Mount Moon, our friends rescue a scientist named Seymour from a batch of Zubat. (Along the way, Brock is able to catch one of the Zubat.) Seymour leads Ash and his friends into a cave to find the legendary Moon Stone, which is said to increase the power of Pokémon. Deep in the cave, Ash spots a Clefairy carrying a Moon Stone. He considers capturing it, but Seymour tells him Clefairy prefer to live at Mount Moon. Ash decides to leave the Clefairy in peace, but Team Rocket shows up with plans of their own! Will Team Rocket steal the Moon Stone? Are there other Clefairy lurking about, and do they carry Moon Stones, too? And is the legend of the Moon Stone true?