Cardcaptor Sakura: Master of the Clow, Book 6

Sakura was an average 4th-grader until the day she found the Clow, an enchanted book of magical Clow Cards. But the cards were missing! Kerberos, the Creature of the Seal, emerged from the cover to warn that if the cards were not returned, they would come to life and do evil. Kerberos made Sakura a Cardcaptor, and their magical hunt for the cards began. The Cardcaptor manage spawned the hit anime and TV series shown on the Kids' WB! network and Cartoon Network.