Tsubasa Reservoir Chronicles

Sakura is the princess of Clow - and possessor of a mysterious, misunderstood power that promises to change the world. Syaoran is her childhood friend and leader of the archaeological dig that took his father's life. They reside in an alternate reality where whatever you least expect can happen - and does. When Sakura ventures to the dig site to declare her love for Syaoran, a puzzling symbol is uncovered - which triggers a remarkable quest. Now Syaoran embarks upon a desperate journey through other worlds - all in the name of saving Sakura.