The story begins with three middle school girls -- Hikaru, Umi and Fuu -- being transported to a magical world known as Cephiro by the pillar, Princess Emeraude. They are taught magic and told they are the Magic Knights of legend, but the girls just want to go home, as is expected of middle school girls. As the story progresses they all grow in their characters and become strong young women, finding themselves and the power within to band together, become friends and attempt save the strange world.
A beautiful tale of friendship, family, and inner-strength, this manga series is one of the best written. Though it's an older work (as reflected by the art style) it's a classic and is a must-read for any die-hard CLAMP fan. And for everyone else, it's just an excellent read.
