After finding out the Beowulf is actually real, Noelle finds herself in Stonegard to seek out more information on the king. You will need either Alfyn or Cyrus for this Side Story, so make sure one of them is in your active party. In the Stonegard Valleys section of town, look for the Wandering Minstrel NPC in the southern part. He is wearing a green shirt and is near the house with someone standing in front of it. Use Inquire/Scrutinize on the minstrel to acquire The Fortress of Everhold information and bring it back to Noelle to finish the quest.