The problem is that he can’t disobey his father’s orders. Any other son could for any other father, but Arthur is the Crown Prince and disobedience from him would be interpreted as a move for the throne. He’s not ready to rule, not yet, and hopes that the responsibility is still years distant.
For the meantime that leaves him with a problem: Uther has ordered Merlin to be whipped and Arthur can’t think how to get him out of it . Whipping isn’t the sort of punishment one takes lightly and plenty of men have died from it in the past, even from a few lashes when their wounds grew infected. Merlin has been sentenced to a dozen strokes, enough to strip the skin from his back.
In the past Arthur has been able to lie or make excuses to the guards, but that won’t work this time. There was finality in Uther’s tone, his gloved hand clenched around the arm of the throne, when he said “That is my final word and in this kingdom my word is law.”
There’s nothing he can think of to do but to wait and help Merlin as best he can afterwards. And the waiting is horrible, of course, in the same way that it’s the worst part of waging a campaign. One’s imagination is almost always worse than reality.
The dungeon walls are thicker than his arm, but even so Arthur thinks he can hear cries and something that might be a sob. He slams his palm into the wall and turns, pacing up and down, torn between trying to block out the sound and straining for any hints as to what is happening. When he hears a chink of metal, Arthur whirls on the spot.
“We’re finished, sire,” the guard says, looking more than a little afraid of Arthur, who bites down his fury and nods instead of snarling.
It takes all Arthur’s self control to walk to Merlin’s cell instead of running, and when he arrives the sight is as bad as anything he imagined: Merlin is sprawled motionless on the bloody straw with long gashes running down his back, the empty manacles hanging on the wall above him.
Arthur runs now, just a few steps, to Merlin’s side and cradles his jaw with one hand.
“Yeah,” Merlin says, and the hoarse, broken sound of his voice makes Arthur wince.
“I’m taking you to Gauis,” Arthur says, lifting Merlin’s body to slide an arm underneath his back, and Merlin moans quietly at the movement. “It’s all right,” Arthur lies, and curls his other arm gently around Merlin’s neck.
He isn’t heavy, or perhaps Arthur is so used to carrying huge swords and wearing armour that he barely notices the weight of Merlin hanging limply as his blood soaks into Arthur’s jacket.
Gauis startles when Arthur kicks open the door to his chambers, and his eyes widen.
“Put him on the bed,” Gaius says, urgently, hurrying to collect his supplies.
Arthur doesn’t leave his side. Not when Merlin falls unconscious from the pain of the alcohol and salt Gauis rubs into the wounds to prevent infection and not through the long hours of the night. He’s still hunched over the side of the bed when Merlin stirs and his eyes open.
“Arthur,” he croaks, “why are you...”
“I’m not leaving,” Arthur says firmly, placing a hand gently on Merlin’s naked shoulder, where they’d cut off the tattered remains of the shirt. He runs a thumb along the collarbone and then up the pale line of Merlin’s neck, soft beneath his fingers.
Merlin takes a shaky breath, his eyes wide, and Arthur wants to make him understand this unspoken, protective thing, the thing that makes Arthur tremble at the thought of Merlin’s suffering or - god forbid - ever having to manage without him.
“I’m not leaving,” he repeats, hand stroking the soft hair at the nape of Merlin’s neck, and Merlin’s eyelids flutter and then close. It’s a tiny, barely discernible movement, but Merlin arches into his touch.
One day when the wounds are healed, Arthur will do this again. Then he’ll be able to watch the brightness of Merlin’s eyes as Arthur’s hands roam over his body, tracing every one of the muscle and tendons that he’s looked at helplessly while Merlin slept. Perhaps Merlin will writhe beneath him and cry out for a different reason entirely, his pink lips parted and sweat running down his temples. But for now there’s just this, giving what comfort he can amidst Merlin’s pain, and he stays there stroking Merlin quietly until dawn.