Note: This takes place immediately after episode 2x13 so beware of spoilers!
Camelot was in a constant state of activity after the dragon's disappearance. Fires needed to be put out, the castle's walls and the courtyard required extensive repairs, and many of the injured remained under Gaius' care for some time. Merlin found himself busier than ever in the days that followed. When he wasn't helping Arthur to survey the damage and organise the repairs, he was assisting Gaius and delivering medicines and other supplies to all corners of the city.
He was on his way back from the lower town when he met Sir Leon coming out of the castle. Leon's arm was in a sling and there was a dark and painful-looking bruise on his forehead; he had taken a nasty fall when the dragon knocked him from his horse. This was the first day that Merlin had seen him up and about, and he gave him a friendly smile and a wave as he hurried past, intent on finding Arthur.
But as he passed by Leon reached out and grabbed his elbow, pulling him to a stop. "What's wrong?" Merlin said, concerned. "Is it your arm? Do you need to see Gaius?"
"No," Leon replied. He glanced around furtively before drawing Merlin away from the guards standing on either side of the castle's doors. "I wondered if I might have a word with you, Merlin."
With an agreeable shrug, Merlin followed Leon down the steps that led to the courtyard. But Leon didn't stop there; he led Merlin away from the men clearing away the debris and making repairs and guided him towards the sheltered walkway. There he stopped and turned to face Merlin with a rather awkward expression on his face. "I know what really happened with the dragon."
Merlin felt as if the ground had opened up beneath him. His heart began to beat faster, and his breaths grew rapid and shallow. "How?" he gasped.
"I saw everything," Leon replied. "Well, almost everything. I lost consciousness after the fall, but when I woke I saw you standing before the dragon, speaking in some strange tongue." He paused, looking more uncomfortable than ever. "I also heard what the dragon said to you. He called you a 'young warlock.' Is it true?"
Merlin nodded miserably.
"Well," Leon said. "That is … interesting."
"Who else knows?" Merlin asked dully.
"No one," he replied. "At least, none of the other knights have said anything. Does the prince…?"
Merlin shook his head. He felt grimly resigned to his fate and wondered distantly, as if it were happening to someone else, whether Leon would tell Arthur first or if he would go straight to Uther.
"I don't suppose it's something you can stop," Leon said carefully. "Your magic, I mean."
Merlin's laugh sounded a little hysterical to his own ears. "No," he said. "That's not how it works."
"Good," Leon said, sounding oddly pleased.
"Good?" Merlin repeated in confusion.
"I saw what you did, Merlin," Leon explained patiently. "You tamed the dragon and sent him away. You saved our lives."
"But it was magic," he protested. "I broke the law."
"You defended Camelot," Leon said. "And for that you have my silence."
Merlin looked at him in astonishment. "I do? You're not going to tell the king? Or Arthur?"
"How could I?" Leon replied, giving him a conspiratorial look. "I hit my head rather hard, you know."
"You did?" Merlin said, still feeling wary and confused.
"I don't remember much of anything after we rode out from the castle," Leon went on, rubbing his forehead absently. "Gaius said that sometimes happens with head injuries."
"But you just said – oh!" Merlin felt his eyes widen. "Are you – are you sure?"
A thoughtful expression crossed Leon's face, as if he was trying to remember something important. "It's no good," he said, shaking his head sadly. "I can't remember a thing. But they tell me that Arthur dealt the dragon a mortal blow."
"I heard that too," Merlin said, smiling tentatively. "I don't think the dragon will bother Camelot again."
"I'm glad to hear it," Leon said, reaching out to clasp his shoulder. "And Merlin?"
"Thank you. For everything."