Tsubasa: Reservoir Chronicle

The series begins by introducing childhood friends Syaoran, a young archaeologist who is investigating a ruin within the Kingdom of Clow, and Sakura, princess of the Kingdom of Clow and daughter of the late king Clow Reed. When Sakura visits Syaoran in the ruins, her soul takes the form of a pair of ghostly wings that disintegrate to other dimensions. As she descends into a catatonic state, the High Priest of the Kingdom of Clow, Yukito, realizes that Sakura is near death. Yukito transports the two to the world of the Dimensional Witch, Yūko Ichihara, where Syaoran begs the Witch to help him save Sakura. There, Syaoran meets two others who each have their own wish: Kurogane, a ninja who wishes to return to his home world after being banished from his world by Princess Tomoyo to allow him to learn what true strength is; and Fai D. Flowright, a magician who wishes to never return to his home world to avoid his king, Ashura-ō. In exchange for the power to travel across dimensions, Yūko demands that each pay with that they value most: Kurogane offers his sword Ginryū; Fai offers the tattoo that suppresses his magical power; and Syaoran offers all of Sakura's memories that involve him. Yūko then presents them with a creature named Mokona Modoki that sends the group on a journey across dimensions in search of Sakura's feathers. After obtaining the first feathers, Sakura awakens from her catatonic state and starts recovering her memories. During their adventures, the group gradually grows closer to the point that Fai jokingly labels them as relatives. As they travel, they learn that the feathers have special powers and can bestow supernatural abilities to those who possess them.
During their journey, the group discovers that Syaoran is in reality a clone imbued with half the heart of the original Syaoran. Several years ago, Fei-Wang Reed, a wizard who caused Sakura's loss of memories, took the original Syaoran prisoner and created the clone to collect Sakura's feathers. With the original Syaoran breaking free of Fei-Wang's hold, the clone loses his heart and becomes an emotionless puppet that follows Fei-Wang's will, betraying the group. The original Syaoran joins in the group's journey with Sakura wishing to save the clone. Foreseeing a future in which Fai kills the original Syaoran forced by Fei-Wang's curse, Sakura gets stabbed in his place, but at the same time splits her body and soul, sending each to different worlds, Seresu and the Dream World, respectively. In the Dream World, the Syaoran clone destroys Sakura's soul when trying to get the feathers. Before her soul perishes, Sakura reveals that she too is a clone of the original Sakura who was also taken prisoner by Fei-Wang. Fei-Wang then takes Sakura's body to use its stored power. The group departs to rescue the two Sakuras learning from Yūko that Fei-Wang is in an alternate dimension from the Kingdom of Clow. Such parallel dimension is the result of Syaoran's wish to save the original Sakura from Fei-Wang's curse various years ago. In order to grant his wish, Syaoran became Fei-Wang's prisoner and Yūko's assistant, Kimihiro Watanuki, was used to replace Syaoran within his original world's history.
The group battles Fei-Wang who destroys the Syaoran clone when he betrays him. He then uses the power of the two Sakuras to revive Yūko, accidentally frozen in time by Clow to halt her death, therein proving himself Clow's superior. Yūko sends the remainings from the clones of Syaoran and Sakura to another world in the past where both are reborn into lives using her life and Clow's magic as payment. They start living together, knowing all of the series' events would repeat. To save their friends from Fei-Wang, the clones seal themselves in Yūko's shop until the battle against him. The group manages to kill Fei-Wang, who traps Syaoran in a void between time and space, dragging both his clone and Watanuki along as a consequence of their connection. With their creator's death, both clones of Sakura and Syaoran fade away leaving behind two feathers. Syaoran and Watanuki escape from the void for a price: Syaoran must continue traveling through the dimensions forever, while Watanuki must stay in Yūko's shop. The group rests in the Kingdom of Clow where Fai, Kurogane, and Mokona decide to join Syaoran once again in hope of finding a way to bring back the clones who still exist as the two feathers. Before departing on their separate ways, Syaoran and Sakura confess their love for each other as they hope to meet again.

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