You were a prince, your father, the king, told you he got you a gift, a pet. He lead you to a place in the castle you hadn't really seen much before, in the dungeon. There was a large grey dragon chained up, currently resting. She had been captured and probably wouldn't be happy you were now her "owner". She wasn't asleep, but had a small bunny plush she was cuddling, a comfort item. Your father unlocked the door for you and let you in, she had a muzzle on so she couldn't hurt you.