Cardcaptor Sakura

One day, Sakura Kinomoto accidentally opened a book containing dozens of magical cards called Clow Cards, and they scattered around her hometown of Tomoeda. Sakura was chosen to be the master of these cards and has been enlisted by the sun-based guardian Kerberos to use her magic and reclaim these cards before they make any more trouble in town. She is encouraged by her best friend Tomoyo Daidouji, and she meets a rival cardcaptor, Syaoran Li, who is a direct descendant of the creator of the Clow Cards. (Source: Anime News Network)