They gave him a choice, in the end: to forfeit his kingdom willingly, or to watch as his son died in front of him, both heir and title stripped away by force. To prove just how serious he was, Hengist dragged Arthur into the centre of the cell by his hair and shoved him to his knees.
“Don’t do it, Father,” Arthur said, glaring up at Hengist with hatred in his eyes. “He’s too much of a coward to actually go through with it. He knows he’ll never win.”
Hengist only smiled, nodding to the sorceress who stood waiting in the open doorway. The woman raised her hand.
After a while, Arthur stopped screaming and lay limp, eyes closed, head lolling against the dirty stone floor. He looked very young, a slow trickle of blood meandering down his chin from where he’d bitten through his lip, eyelashes feathered white against his pale skin. Uther thought of the tow-headed boy he had once held in his arms, the boy who had always dreamed of becoming a knight.
“Last chance, Uther,” Hengist said, resting his boot against the delicate hollow of Arthur’s throat. With enough pressure he could snap his neck, crush his windpipe. Kill him. “Camelot, or Arthur. It will be easier for me if you choose the latter, but I’m not averse to a bit of hard work when the rewards are so great. Either turn your crown over to me, or I will end your filthy bloodline here and now, and take you with it.”
The word didn’t come from Uther’s mouth. Like the others, he turned towards the corner of the cell to where Arthur’s manservant stood forgotten, hands held out in front of him as the shackles dropped cleanly from around his wrists. The fetters were glowing red-hot where his skin had touched them, but the sound they made when they hit the stones was the ordinary chink of metal, like a coin falling to a cobbled street.
“Step away from him,” Merlin said, his hot gaze fixed on Arthur. “Or I swear by the oath I gave him, you won’t live to see another sunrise.”
Uther couldn’t summon up the energy to feel surprised. There had always been something about Merlin: something that was now written all over his face, in the glow of his eyes and the power that crackled from his outstretched palm.
“I would do as he says, Hengist,” Uther said, very calmly. He saw the boy flinch at the sound of his voice, but Hengist didn’t. “You don’t know what you’re dealing with.”
It was painfully obvious that they were out of their depth; a sorcerer who could bend cold iron should not exist, let alone stand before them in defence of his prince. Under any other circumstances Uther might have thought to be angry, or even afraid, but as it was he felt only the need to end it.
“Step away from my son!” he snapped.
Hengist’s boot came down.
Uther was never sure, afterwards, if it was an accident or even a reflex, or if Hengist, like Arthur, thought his opponent lacked the courage to follow through on his threats. Merlin didn’t give him the chance to explain. In moments, Hengist and his henchmen were blasted back across the width of the cell, hitting the stone wall opposite with an audible crack. They lay in a crumpled heap on the floor, and Merlin turned towards the sorceress, who dropped to her knees with a gasp and bowed her head.
“Emrys,” she breathed, sounding terrified. “Forgive me.”
“Get out,” Merlin told her coldly, and Uther had heard that tone before, but not from him. “I know what you were trying to do, but this is not the way. I will not spare you if you try to harm Camelot again.”
The woman nodded and scrambled to her feet, running out of the dungeons without a backward glance. Merlin ignored her in favour of kneeling next to Arthur.
“Sire,” he whispered, and of a sudden he was just a boy again, his hands trembling as they passed over the prince’s broken form. “Arthur, please wake up.”
For a sickening moment, Uther thought that Arthur would not wake—that he'd be forced to bury the last of Ygraine in this godforsaken tower. Then the prince stirred, one hand coming up and groping blindly to stroke over the curve of Merlin’s hair.
“Such a girl, Merlin,” he murmured hoarsely, and though his voice was weak even Uther could hear the affection in it. “Always so dramatic.”
Merlin uttered a strangled little laugh, and Uther’s knees gave out, sending him sliding to the floor beside his son with a thump. For the first time, Merlin seemed to remember that he wasn’t alone.
It was a fraught moment. For a time, the two of them merely looked at one another, sizing each other up like opponents on a battlefield. The boy could have incinerated him with a thought, Uther knew, but chances were, he wouldn’t. To kill him would be to harm Arthur, and Uther had already seen enough to know that Merlin would never do that.
Likewise, Uther could strike him down. His hands were tied for the moment, but when they got back to Camelot he could clap the boy in irons and have them cut off his head, and the look in Merlin’s eyes said that he would probably let him.
But if he did that, Arthur would never speak to him again.
Moving very slowly, Uther held out his hands, palms upward, letting the boy see the rawness where the shackles had bitten into his wrists.
“Thank you for saving him,” he said stiffly, the words tasting like stones as they came out of his mouth. It went against his every instinct to trust a sorcerer, and from the wary look on Merlin’s face he felt much the same. But Arthur’s eyes were open and blue and watching them closely—and for his son, he had done much worse things.