The Isolated Plateau

"The Isolated Plateau" is a Main Quest in.

Overview
Link obtains the quest after descending the Great Plateau Tower, at which point the Old Man glides in on his Paraglider to talk with Link. The Old Man tells Link about Calamity Ganon, who is trapped in Hyrule Castle but will eventually break out. He asks Link if he will go to the Castle, then tells him that if he wants to leave the Plateau, he will need a Paraglider. He offers Link his Paraglider in exchange for treasure from a location nearby. He's really asking Link to visit each of the four Shrines on the Plateau and earn their Spirit Orbs, but for some reason he seems like he wants to be vague about that.