The young swordsman squinted out at the desert. “What do you think it is, Sir Isaac?” He drained the last of the canteen, then spit the lukewarm water over the edge of the parapet with a grimace.

Isaac was just coming up the stairwell, polishing his sword with a square of cloth. “Should have swallowed that. We’ll be on short rations until we take the oasis.” The knight glanced up at the sun, which was perhaps an hour from its slumber beyond the horizon. Squinting himself, he peered out at the glint of light atop the dune, perhaps a thousand paces outside the fortress wall.

“You see it? Looks like someone left a sword out there. I thought we gathered them all after yesterday’s battle.”

“Apparently not,” Isaac replied coolly. He regarded the younger soldier’s curved scabbard, and the ornate hilt emerging from it. “I see you’ve got yourself a nomad’s blade.”

Grinning, the soldier glanced down at his own sword admiringly. “It’ll hold me over until I get one like yours,” he said, nodding at the knight’s unsheathed blade. Even at this distance, he could see the sky in Isaac’s sword, a reflection creased with the nicks of battle.

“Indeed.” Isaac narrowed his eyes once again at the light in the desert. His left hand still polished the blade with an uneven rhythm, the cloth jumping back and forth across the steel.

“Sir Darren said he’d make me his squire if I made something of myself in the desert campaign,” the soldier said, his eyes distant, his mouth grinning still. “Not bad for a merchant’s kid, and a half-blood at that.” He turned and leaned against the parapet wall, looking back at the single tower of the fortress.

Isaac looked down at his sword for a moment, tilting it in the slowly fading light. Then, the rag moved once again, up and down the blade. “See that you do. This kingdom needs more low-born knights.”

“Amen,” the soldier agreed, turning back to the desert. He went to grab his empty canteen, then remembered. “Right.” With a shrug to himself, he threw Sir Isaac a glance. “I’ve heard that your mother was a nomad too, sir. Like mine.”

“Quite right.” Isaac stuffed the rag into his belt and sheathed his sword with a heavy clink, giving the young soldier a hard look. “Several have made an issue of it, and lived to regret it. I suggest you don’t.”

“Of course, sir. My apologies.” The young man lowered his head, surreptitiously looking back out at the dunes. As he did, the light flickered twice, and disappeared. The soldier raised an eyebrow. “Huh. What do you make of that?”

Isaac flicked his eyes at the missing glint and walked back toward the stairs. “The sun’s setting. It isn’t in the light anymore.”

“Of course, sir,” the soldier repeated. Something in his voice made Isaac pause, turn back to the swordsman. His eyes remained on the desert, averted from the knight. Sir Isaac shook his head and descended the stairs.

The swordsman waited until the knight was out of sight, then silently drew the dagger from his boot. Lifting it above his head, to catch the light of the setting sun, he signaled to the swordsmen waiting atop the distant dune. Confirm?

Slowly, the reply came. Sir Isaac. Returning to base.

Serrata only nodded and sheathed his dagger. The half-blood swordsman sighed, remembering when his mother had taught him the nomad’s signaling code. He’d used it in childhood games, flashing the signs for attack and retreat to his friends.

It would be only minutes before the men returned with the spyglass and the signaling mirror, and a handwritten copy of the traitor’s message, sent by light of sword.