"Gaius," he hears behind him, softly, and he turns without hesitation. He sees Arthur less frequently than he sees Morgana these days, unless he's come for Merlin, but he loves the boy no less for it.
"Sire," he says, bowing his head. Arthur nods back distractedly, keeping a formal distance at the doorway, a troubled look on his face. Gaius takes this in and knows that this is more than a social call, or a search for a wayward servant. "Is there something wrong?"
Arthur meets his eyes for a grave second, with something of Uther's impenetrable stare. "May I speak with you?"
"Of course. Come in, come in," he says, setting his book aside and waving a hand in welcome. He watches Arthur take a few steps closer, looking about the cluttered room, but Gaius thinks he's only paying attention enough to keep clear of any hindrances. He stops at the edge of the workbench and rests a hand on its scarred edge.
"Don't mind the mess," Gaius says, and shakes his head. "I think Merlin spends most of his tidiness on you."
"What little there is of it," Arthur says, his manner growing wry for just a moment. He rests his free hand on his hip as Gaius chuckles.
But Gaius doesn't miss Arthur's thumbnail worrying at the grain of the workbench, though he gives no sign that he's noticed. One of the few gifts of advancing age is the ability to feign oversight of the little things. He sets about tidying a spilled satchel of cloves and waits for Arthur to speak his mind.
He hasn't long to wait--Arthur would not have come had he not already chosen his course. "Gaius," Arthur says, meeting his eyes, "is it possible that whatever is troubling Morgana may be... catching?"
Gaius straightens at that, dusting his hands off on his robes. "Has she taken ill? I'll get my bag--"
Arthur stops him with a raised hand. "No, nothing like that." Then he shakes his head and in a low voice, he says, "I've been having... dreams, lately. The same one, for a few nights, now."
Something inside Gaius grows cold, though he does his best not to show it. "What sort of dreams?"
"Water," Arthur says, and his body stills, though his eyes are far away. "Murky water, closing over my head, and I cannot move."
As Morgana foresaw, and as Merlin saved him from. Arthur is seeing not the future, but the past, and Gaius gives Arthur a gentle smile, as much to reassure him as to vent his own relief. "I do not believe this is the same malady Morgana suffers from, sire. A blow to the head can often--jostle the brain, as it were. These nocturnal phantoms are just the mind resettling itself." Arthur looks distinctly uncomfortable at the reminder of his fictitious injury, and Gaius turns away to give him a moment, sorting through several small vials for show. "I can get you a sleeping draught, if the dreams are troubling you too much. It sounds most unnerving."
"That won't be necessary." Arthur leans his back against the workbench and crosses his arms over his chest. "Just when all seems lost, a hand reaches me through the water, and I am pulled to the surface." He looks up at Gaius again, his gaze clear. "And then I wake up."
Gaius smiles. "Then it seems that your dreams have granted you a protector as well, my lord."
Arthur looks surprised. "I hadn't thought of it that way."
Gaius folds his hands together and nods to Arthur, thinking of the boy who actually did the saving. "It has been my experience, sire, that aid often comes from the unlikeliest quarter."
"And sometimes it comes from our steadfast friends." Arthur gives him a small, but genuine smile, and inclines his head in thanks.
There's a commotion in the hall, and Merlin comes bustling in, head down as he rummages through the bag slung across his shoulders. "Gaius, you would not believe what I had to look under to find--" Merlin stops short on seeing the prince. "Arthur. I thought you were out on patrol. Was there something you needed?"
Gaius watches Arthur's demeanor change instantly, head going up and shoulders squaring as he faces Merlin. "A servant I can rely on, but instead, I seem to be stuck with you."
The words are harsh but the tone isn't, not really, and Gaius watches Merlin brush the insult aside with a toss of his head. "Right, sorry, I'll get right on doing the work of four or five, instead of just three."
"One would be sufficient," Arthur says. "My chambers are filthy, and my horse needs reshoeing. Gaius," he adds, with a nod, before sweeping out of the room.
"Probably tried to kick him off." Merlin wrestles the bag off with a grin and drops it on a chair. "Duty calls," he says, giving Gaius an exaggerated bow, before turning and jogging after Arthur.
Gaius listens to their voices echo down the hall, fading with distance. Sentimentality is another indulgence that age allows, and he lets loose a fond smile, where neither of them can see it.