You were flying in the sky around Skyloft with your loftwing when you fly next to a yellow column. As you do so, you hear a voice calling for help.

Meanwhile, Impa was the one who called for help as she's in difficulty against Girahim in front of the Door of Time of Lanelle's Refinery. Link isn't out of it, so he can't help her, and Girahim is about to defeat her to capture Zelda that Impa is protecting.