Once Sakura captures all of the cards, she is tested by Yue, the cards' second guardian, to determine if she is worthy of becoming the cards' true master; Yue is also the true form of Yukito Tsukishiro, Toya's best friend. Aided by her teacher Kaho Mizuki, Sakura passes the test and becomes the new master of the Clow Cards.
Eriol Hiiragizawa, a transfer student from England, arrives in Tomoeda and begins causing disturbances with two guardian-like creatures, Spinel Sun and Ruby Moon. Suddenly unable to use the Clow Cards, Sakura transforms her wand and begins the process of transforming the cards into Sakura Cards. Once all the cards have been transformed, Eriol tells Sakura that he aided her in converting the cards so they would not lose their magic powers. Syaoran later confesses his love to Sakura, who comes to realize she also loves him.
Cardcaptor Sakura concludes with Syaoran returning to Hong Kong with a promise to return. Two years later, Syaoran moves back to Tomoeda permanently.
P/S: Reminds me of Tsubasa Chronicles. Oh yeah, I'm one of Clamp's fans, anyone? Don't deny your childhood, la. Animax and all of that.
Source: http://en.wikipedia.org/wiki/Cardcaptor_Sakura