Time to go back to Shamanock, the castle in the sky and save princess Zelda again.
DX Version - Zelda Classic 1.92(183) or higher
http://www.purezc.com/index.php?page=quests&id=87
Original Version - Zelda Classic 1.90 or higher
http://www.purezc.com/index.php?page=quests&id=75