Card Captor Sakura
A story about a girl who accidentally opened a book that contains magical cards. Due to her mistake she is tasked by the guardian of the book, Kero, to collect all the cards. Later on... she becomes the new mistress of the cards and was put to the test by the other guardian of the book, Yue. Soon... mysterious events happen in her hometown and she is now tasked to convert all the Clow cards to Sakura cards.