Macao did not immediately lead the others after the tracks.
First, he had the repairman reset Tower One's positioning dial to the correct direction. Then he used his communication crystal to notify the canyon entrance to temporarily bar all caravans from entering.
"Now they'll know we've discovered what they did," Lin Yuan said.
"Better than letting people who don't know what's going on keep walking into a trap."
"What if they run?"
"Then we'll catch the slowest one."
Macao spoke casually, but his hands never stopped. He laid the half-length of hemp rope, the loosened bolt, and the map together, then carefully compared the wind direction with the locations of the old trade routes.
"Tower One only guides caravans to the entrance. Tower Three is what really determines which route they take. But the saboteurs extinguished Tower Two as well, which means they weren't just trying to change the direction."
The repairman quickly caught on. "They didn't want the signals to contradict one another."
"So at least three of the seven towers have been tampered with."
"Possibly all of them," Lin Yuan said.
The mountain path to Tower Two had been blocked by a rockfall.
Lin Yuan stood before the severed path. His spatial perception reached past the rubble and quickly found the other end. Rather than take the other two straight through, he first picked up a pebble and tossed it into the folded space.
Only after the pebble landed safely on the other side did he bring the two ends of the path closer together.
"The part we can't see might have collapsed," Lin Yuan explained.
Tower Two looked intact from the outside, but its door was locked from within. A steady hum came through the crack, and the air around it kept surging faster in bursts.
Lin Yuan was just about to touch the door handle when Macao grabbed his wrist.
"Don't open it yet."
He lit a small ball of purple flame and brought it close to the crack. The flame was immediately drawn out into a thin streak, almost flattening against the stone wall.
"There's a wind-gathering device inside."
The repairman turned pale. "If the tower door opens, all the accumulated wind will rush out."
"The crosswind that hit Tower One came from here too," Lin Yuan said.
Lin Yuan pressed his palm against the wall beside the door and folded the distance between the space behind it and the exit at the top of the tower. The moment Macao cut through the lock, the gale stored inside did not rush at the three of them. Instead, it passed straight over the stone chamber and burst into the sky from the top of the tower.
The roar continued for more than ten breaths.
The repairman hunched his shoulders as he entered the stone chamber and removed four cyan Magic Crystals from beneath the signal crystal.
"Portable wind-element magic devices. You can buy them on the market. Once activated with magic power, they can run on their own for half a month."
A crumpled piece of paper had been tucked beneath one of the crystals.
It listed the dates, numbers of people, and cargo of several caravans passing through the canyon. The most recent entry had been circled in red ink.
Royal capital medicinal herb caravan, twelve wagons, arriving tomorrow at dusk.
Only static came from Macao's communication crystal. Tower Three was still interfering with communications deep in the canyon.
"Didn't the entrance administrator already ban passage?" the repairman asked.
"This caravan enters the canyon from the north. They can't receive the notice from the south." Macao pointed to the map. "On their original route, they'd see the signal near Tower Three and then decide which trade route to take."
"There's still a day," Lin Yuan said.
"The paper is old." Macao touched the ink of the red circle. "It was written at least ten days ago. If the caravan set out early, they could arrive today."
He wasted no more time. Leaving the repairman to restore Tower Two, he hurried toward Tower Three with Lin Yuan.
There was no road between the two ridges, only a suspension bridge that had broken long ago. Lin Yuan folded the two ends of the bridge together and crossed the deep valley, stepping on the half-length of planking that remained.
The closer they got to Tower Three, the more signs of human activity they found along the way.
Wheels hidden in rock crevices, caravan markings carved into the rock walls, and campfires that had yet to go out. Someone had been watching the main road from here for a long time and sending information on passing caravans north.
No signal shone from the top of Tower Three, but fresh wheel ruts marked the old road behind it.
Twelve wagons.
The wheel tracks entered the abandoned northern road in an orderly line, but none came back out.
Lin Yuan crouched and touched the soil. "No more than two hours."
Macao looked toward the end of the northern road. There lay a narrow valley enclosed on both sides, ideal for intercepting a convoy.
He took out a sheet of flame communication paper and lit a corner. The paper turned into a purple firebird, barely making it through the signal interference as it flew toward the canyon entrance.
"Notify the local guards and have them seal the exit."
"What about us?" Lin Yuan asked.
"We go after them."
The two picked up speed as they followed the ruts. As they crossed the last rocky slope, they heard horses screaming and wooden crates overturning in the distance.
More than a dozen masked people had already blocked the mouth of the valley, their magic guns and crossbows all trained on the trapped caravan. More people lay in ambush on the rock walls above, preparing to cut the ropes securing the boulders.
Once the boulders fell, the twelve wagons would have no way to retreat.
Lin Yuan raised a hand toward the ropes.
But Macao put a hand on his shoulder, his gaze fixed on the center of the caravan. Several canvas-covered wagons carried no scent of medicinal herbs. Instead, the edges of standard-issue armor showed beneath their beds.
The drivers surrounded by gun barrels showed no panic either. They held the reins, their hands all poised where they could draw their swords at any moment.
"This isn't an ordinary medicinal herb caravan," Lin Yuan said.
"Looks like the guards in the north spotted the problem before we did." Macao grinned. "They deliberately spread the news and used themselves as bait."
Below, a masked figure raised a magic gun and gave the leader a final warning.
The canvas covers on all twelve wagons were thrown back at once.
Rows of armor gleamed in the sunlight, and the smug looks on the ambushers' faces froze instantly.