Arthur had learned this trick from his father. His father hadn't, of course, just come out and told him this one. All of Uther's best lessons had been implied or learned by watching. All the same, Arthur knew the trick inside and out; he'd seen his father use it. Now, whether Uther had been witting or unwitting, Arthur didn't know. But he found it didn't matter much.
He didn't have a chance to put his father's lesson to work until the day when the guards came in, dragging a very disheveled Merlin and followed by a smirking Lord Hart. Arthur hated Lord Hart. So did Merlin.
Thus, he knew right away that this was probably bad.
"Sire," said Lord Hart with that puffy-chest thing that always made Arthur wonder how he managed to fill his lungs so fully without popping. "Your servant, Merlin, has been caught doing magic. By me."
Arthur stopped looking at Hart and turned his glare to Merlin. Of course the idiot got caught. Of course he did.
"I suppose you think that he ought to be executed then?" Arthur guessed in a very kingly manner.
"Arthur, I'm sorry—" Merlin started, but Lord Hart cut him off.
"It is the law, Your Highness. Your father always upheld that."
People still thought Arthur could be convinced by comparing him to his father. You, sir, he thought at Lord Hart, did not know my father. Arthur had vivid memories of Uther sentencing people to death for magic… Like, for example, that Alice woman that Gaius had been so attached to. And Merlin himself had been arrested a few times.
"Yes, and I suppose I should follow the example of my father, shouldn't I?" said Arthur, and if anyone in the room caught the sarcasm, they did not say so. "Very well. Merlin is sentenced to death at dawn."
Merlin looked promptly horrified. "Arthur!" he cried.
Arthur shook his head at Merlin, and his eyes were enough to shut him up. "Take him down to the dungeons. I'll be down to interrogate the sorcerer soon. Start building a pyre." Again.
And it was only after Merlin, looking confused, and Lord Hart, looking gratified, were out of the room that Arthur rolled his eyes and sank back in his chair.
Gwen woke him up at two in the morning. "Arthur, Arthur!"
He rolled over. "What?"
"The warning bells! Someone has escaped the dungeons. Do you think it's Merlin?"
Arthur looked at her for a second. "It had better be," he said at last, yawning and rubbing his eyes. "Can I go back to sleep now?"
She nodded, so he turned in his bed, snuggled down into his pillow, and began to slumber again.
A/N: So, in case you didn't guess, this was sort of intended to be a bit of a companion/sequel thing to "Same Old Story", because Uther never can get anyone executed. Poor man. If they just let him kill someone, he might not have had so much pent up anger. And I just think Arthur would have picked up on that.