Syaoran, Kurogane, Fai, and princess Sakura continued their journey searching for Sakura's feathers...And landed into a kingdom that was trapped inside a bird cage. Everyone in this kingdom was given their own birds thanks to a magical bell from the kingdom's princess.
This kingdom was ruled by an evil king who found an amazing source of power that created the cage that trapped the kingdom inside and princess Tomoyo's bird. And without princess Tomoyo's bird, she could no longer talk. The four explorers soon realized that this amazing source of power was from one of Sakura's feather.
But for now, they must protect the princess Tomoyo from her uncle( the king ), who tries to steal her power and turn the kingdom into a place filled with darkness. Princess Tomoyo knew that she would be captured by her own uncle one day even though she found a good hiding spot, so when she met princess Sakura and Syaoran, she gave a special ring to princess Sakura that could help her stop the king from succeeding his plan. So the group must help princess Tomoyo to stop her uncle and return Sakura's feather to its true owner.
an extended description!