Recovering the Hero's Sword Main Quest

In-game Description

The darkness-sealing sword, the Master Sword, vanished in the Temple of Time on the Great Sky Island.
The Deku Tree can feel the sword’s presence and says that the Master Sword is moving. What could that mean…

The Master Sword is moving because it can be found on the back of the Light Dragon that roams the skies of Hyrule. You can access it more easily by waiting for it to approach a Skyview Tower, using the tower to fly up in the air and land on its back. Or fall from the Sky Islands and land that way.

After finding the Master Sword:

You found the Master Sword with the white dragon soaring in the skies. The legendary sword that seals the darkness has returned to your hand, along with Zelda’s wish.