"You can thank Myst for Ragnar," Aaron said with a laugh. "It belonged to his family and, when his powers manifested, his parents used it to hide him from the hunters. When they died he gave it to the Underground as one of its bases of operation. Its a huge castle, packed with enough food and drink to survive a very long siege and which has only two safe ways in and out of it, every other route is booby-trapped. Luckily for us Myst knows which are the safe ways in."