Syaoran, a boy who wants to become an archaeologist, and Sakura, a princess from the Clow Kingdom, are childhood friends with a close relationship. On a fateful night, Sakura lost all her memories as a result of a conspiracy to obtain her powers. In order to regain her memory, Syaoran seeks help from the witch, Yuuko. Yuuko tells Syaoran that he has to travel from one alternate reality to another to collect fragments of Sakura's memory. However, even if Sakura regains her memory, she will have no recollection of Syaoran. Traveling together with them is Kurogane, a warrior who was exiled from his country, and Fay, a magician who wants to escape from his King. With the help of a magical creature, Mokona, they set off on an exciting journey through time and space.

Source: ANN

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Alternative setting: Chobits
Alternative setting: X (2001)
Alternative setting: Magic Knight Rayearth
Alternative setting: Kidou Tenshi Angelic Layer
Alternative setting: X
Alternative setting: Clamp Gakuen Tanteidan
Prequel: Tsubasa Chronicle
Same setting: xxxHOLiC
Sequel: Tsubasa Tokyo Revelations