Merlin reined in his horse at Arthur's side. The courtyard was filled with mounted knights, their horses' hooves beating a tattoo of metallic echoes on the paving stones. The rest of the troops waited below, lining the streets all the way into the lower town.

Arthur bent down and gave Guinevere one last kiss. They'd said their farewells earlier that morning in the privacy of their own chambers, and now a silent look of entreaty passed between them.

"Be safe," Gwen whispered against Arthur's cheek. He nodded, and letting go, he straightened in the saddle.

Gaius, seated in the driver seat of a cart behind Merlin carried medicines and field hospital supplies. On the steps behind Guinevere, Bri stayed behind as Camelot's acting physician in Gaius' absence, her face an inscrutable mask.

For the tenth time Merlin kicked himself for not saying a proper farewell to her.

Things had been so hectic over the last few days, since receiving Queen Annis' call for aid. The Saxons had gathered in strength and advanced across her lands. They were now a week away from Annis' stronghold. If all went according to plan, Camelot's army would reach Caerleon's capital in three days' time, and would march out along with Annis' armies to Barladin, the field of battle chosen by Arthur. It would give them the advantage over their enemy. But the timing was tight, and any delay could be fatal.

Emrys had been busy collecting allies and counseling the King. Merlin had been busy getting Arthur ready for the journey. It was Gaius alone who hadn't needed him. Bri had taken over scrubbing the leech tank, washing the floors, and preparing supplies, as it was due in her role of apprentice. Merlin had barely seen her since their last talk, and even then, briefly and on the run. And now he kicked himself for not finding the time. Would she care if he didn't return?

Merlin looked up again and found Bri watching him.

"We ride to Caerleon!" Arthur called out, and the knights turned their mounts about. Reluctantly, Merlin broke eye contact with Bri and followed Arthur out of the citadel gates with an unsettled feeling in his stomach and a heavy heart.

Gaius' cart followed them and the columns of mounted knights. The army parted to let them pass as they made their way through the upper and lower town, and then fell in behind them.

Their pace throughout the day was brisk, and close to dusk Merlin's bones ached all over.

"Gods, how I hate being on a horse all day," Merlin muttered throwing Arthur a side glance.

"You're such a complainer, Merlin. Do you know of any faster way to travel?"

Merlin's eyebrows shot up cryptically, and Arthur narrowed his eyes at him.

"Not for an entire army, I don't," Merlin conceded.

Arthur glanced around them. They were sufficiently far ahead of the knights to be out of earshot.

"Don't tell me you can fly, Merlin!"

"In a manner of speaking."

Arthur stared at him then scoffed.

"Like, on a broomstick?"

Merlin grinned. "I've never tried that but I suppose it is possible, if not horribly uncomfortable. Even more uncomfortable than riding a horse for ten hours straight. Ugh! Why would anyone do it?"

"So, if not a broomstick, then how?"

"Maybe one day I'll show you."

Arthur pulled back cautiously. "Oh, no! I prefer my horse, thank you!"

Darkness would be upon them soon, and Arthur called for a halt. The troops stopped and set up tents for the night. They started fires and cooked dinner. Arthur's closest knights had found their way to him. They sat around the fireside eating.

"Deep in thought, Gwaine!" Elyan baited his friend playfully. "Thinking of some maiden you've left behind?"

"He's thinking of all of them, yeah," Percival laughed, and Gwaine made a swipe at him that Percival ducked.

Arthur watched them amused. He shared a smile with Merlin.

"Is it perhaps Gaius' new apprentice?" Elyan pressed on. Gaius raised an eyebrow.

Merlin's smile dropped and he became suddenly fascinated by a little speck on his boot.

"Nah, I don't think Bri fancies our Gwaine," Percival jibed. "Not that he hasn't tried." Gwaine punched his shoulder and Percival shoved him back playfully.

"Never say never, that's my motto," Gwaine said with a laugh.

Arthur elbowed Merlin in the ribs. "Well, at least he's tried," he said softly so that only Merlin could hear him. Merlin scowled at the little speck on his boot.

Arthur watched him and shook his head.

Oblivious, the knights joked on, turning to Mordred and teasing him about his girl. Mordred made easy prey by blushing.

When the others had gone on to sleep, Merlin brooded alone by the fire. He felt like a puppeteer holding so many strings that he could barely distinguish his own. Emrys was to join Arthur once he reached Caerleon. Merlin would have been sent on an errand back to Camelot. He had sent a letter containing a warning and a call for help to Alator of the Catha but had received no answer from him yet. He hoped Alator was not in Morgana's clutches, but he had no way of knowing unless he went to search for him himself. And that he could not do. His place was at Arthur's side, especially on the eve of battle.

The fire dimmed a little and Merlin, sleepless and restless, added more logs to it and kept his vigil. He wondered if back in Camelot, Bri had already gone to sleep.

...

In the dark of the forest, not many miles away from where Arthur's army rested, a small group of armed men camped for the night without fires. Their weapons were sheathed and their horses' hooves covered and tied up in skins.

The only sound was the whimpering of a man who lay thrashing on the ground. His arms were bare and on his wrist a three pronged tattoo was visible, the druidic symbol.

Above him, like a shadow, stood Morgana in her dark robes, her eyes glinting feverishly. She held in her arms a velvet lined wooded box that contained the little serpent-like creature called the Nathair. The Nathair had already done its job. The bites on the Druid's neck were bright red in contrast with his pale skin.

"Let me ask you again, then," Morgana said, her voice sharp like the edge of a dagger. "What do you know about Emrys?"

The man twisted on the forest floor, and between gasps of pain, whispered, "He serves Arthur Pendragon. He is not who you think."

"Who is he?" she asked crouching over the man, her claw-like hand gripping his throat.

"He is," the man gasped, "he is Merlin."

In surprise, Morgana let go of the man's throat. She stood and took a step back, her face a mask of shock and fury.

"Merlin," she spat the name like it was poison on her lips. "That troublesome fool! Impossible! I had him in my grasp so many times! So many chances to kill him," she whispered thinking back. "I have to know for sure. And if it's true, I will not fail again."

She stepped forward and placed her booted foot on the man's throat. She pressed down until she heard a dull snap. The man's thrashing stopped. She stepped over him and melted into the forest.

Behind an oak tree, not many feet from the dead druid, a shadow appeared, a hooded man holding a staff. He walked silently to the body, and after looking cautiously around, he lowered his hood.

Alator of the Catha crouched down and whispered a few words over the dead druid, closing the eyes that bulged open with terror even in death. Without a sound, he rose to his feet, looked around him and disappeared into the forest, in the opposite direction that Morgana had taken.