Hikaru, Umi and Fuu are Tokyo schoolgirls with nothing else in common, until one fateful day changes everything: the three are summoned to the magical realm of Cephiro and find that their lives are inexorably intertwined.

Fourth grader Sakura Avalon finds an old book in her father's library. When she opens it, cards fly out and disappear. She learns the cards are Clow Cards--magical creatures who take the shape of cards. Now that the Clow Cards are loose, terrible things could happen. She must recapture the cards. That's how she became Cardcaptor Sakura.