"Director, Sheng Lan. Jiachen has written something else."
Forty hours after those words, Jiachen was no longer marking ambush points.
May 13, C.E. 71, deep in the Libyan Desert of North Africa, nine kilometers south of the East Asia Test Detachment's temporary encampment.
Han Zheng crouched Black Iron Unit One in the shadow of a weathered Rock Hill, switching the panoramic screen to passive optical mode at maximum magnification.
On the screen, a vast cloud of sand was rising from the Dry River Valley seven kilometers away.
Four-legged silhouettes emerged through the curtain of sand. The angles of their bent joints closely resembled those of canines, and every step came with visible suspension cushioning.
Baku.
The primary ground Mobile Suit of ZAFT's Desert Tiger, Andrew Waltfeld.
Tian Mu's voice came through from Unit Two's channel, unable to hide his astonishment.
"Han, that thing is faster than I imagined."
"How fast?"
"Jiachen measured it. One hundred seventy kilometers per hour. On sand."
Han Zheng locked the optical tracker onto the lead Baku, magnifying the rhythm of its four mechanical legs until every movement was clearly visible.
"More than just fast. Look at how it crosses the dunes. Its forelegs probe first, then brace; its hind legs retract and kick out in sync. Its center of gravity always stays pressed over the middle of the body."
Liu An added in a muffled voice from Unit Three.
"Just like a real desert wolf."
Sheng Lan's voice cut in from the communications vehicle.
"Han Zheng, do not expose yourselves. All three units are to maintain thermal-radiation concealment. Keep output at minimum power. Jiachen, archive all kinematic data."
"Understood."
Han Zheng released the controls and let Unit One remain completely still on the shaded side of the Rock Hill.
The scene on the screen continued to unfold.
There was more than one Baku in the formation. There were six.
They were spread out in a column along the Dry River Valley, in pairs, roughly one hundred fifty meters apart.
They were heading south-southeast, at an angle of no more than twenty degrees from the Archangel's estimated route.
Ye Qingluan's voice came from the rear of the communications vehicle. The static in the channel indicated that she was intercepting ZAFT transmissions with a handheld antenna.
"Han Zheng, there are encrypted calls on the ZAFT frequency. Waltfeld's command codename appeared twice."
"He's on site?"
"Most likely. Waltfeld has a habit of personally leading reconnaissance missions. ZAFT Africa Front combat reports have recorded it at least four times."
Sheng Lan opened the tactical terminal in the communications vehicle. On its screen, the Archangel's estimated position lay fourteen kilometers to the southeast, moving along the valley's edge at thirty kilometers per hour.
The Baku formation's heading was slowly converging with the Archangel's route.
"Director, Waltfeld is closing the trap."
Lin Yuan's voice came back over the encrypted channel from eight thousand kilometers away. Faint machinery could be heard in the background; he was still in the analysis room at the 811 Institute.
"What's the Baku's weapons configuration?"
"Beam Rifles paired with missile launchers, and claw shredders for close combat. Intelligence from Tariq indicates that Waltfeld usually uses the first two Baku pairs for diversionary harassment, driving the target into a prearranged fire zone, while the third pair cuts off its retreat."
"How do you assess the Baku's close-combat performance?"
Sheng Lan pulled up the kinematic data recorded by Han Zheng and glanced over the key parameters.
"Director, the quadrupedal configuration exerts more than sixty percent less ground pressure on sand than bipedal Mobile Suits. Combined with its low center of gravity, its lateral acceleration and deceleration far exceed those of standard humanoid Mobile Suits. If Black Iron gets tangled up with a Baku at close range in the desert, overheated joints and unstable footing in the sand will put it at a severe disadvantage."
The sound of Lin Yuan tapping the desktop came through the channel.
"Not a disadvantage. A design compatibility issue."
"What do you mean, Director?"
"Waltfeld gave his Mobile Suits four legs not because he likes wolves, but because he understands that desert warfare follows different rules from space warfare. Terrain determines form, and form determines tactics. That is the right approach."
Hearing that in the cockpit, Han Zheng ran his fingers over the control stick.
"Director, then how should Black Iron fight a Baku in the desert?"
"Don't chase it. Make it come to you."
Lin Yuan's pace did not change.
"The Baku's strengths are speed and terrain compatibility. Its weakness is thin armor. Its Beam Rifles and missiles have high fire density but limited penetration. Against Ceramic Steel frontal armor, their effective damage range will be greatly reduced."
"Director, are you saying we let it charge in, take its fire head-on, then use the Bombard Gun at close range?"
"How many seconds can your Ceramic Steel withstand its Beam Rifle?"
Han Zheng recalled the test data Xu Yanqiu had given him.
"Under continuous fire on the frontal armor, surface cracking begins after four seconds and penetration occurs after seven. A single hit cannot penetrate it."
"If a Baku charges at one hundred seventy kilometers per hour, how long does it take to go from effective range to close contact?"
A calculation result automatically appeared on Jiachen's tactical screen.
Han Zheng read it aloud.
"Five point three seconds."
"A little over five seconds. Does Jiachen have simulation data on the Baku's hit rate while firing on the move?"
"Yes. At high speed, its hit rate against a stationary target is around forty-seven percent."
"With a forty-seven percent hit rate, no individual hit lasting more than zero point five seconds, it can score at most two or three effective hits within five seconds. A single hit cannot penetrate Black Iron's Ceramic Steel frontal armor."
Lin Yuan's voice paused for a beat.
"Wait until it is within three hundred meters. Fire the Bombard Gun directly and cover its maneuvering arc. The Baku's armor cannot withstand the internal blast pressure of even one Bombard Round."
Han Zheng's knuckles tightened around the control stick.
"Director, this tactic has one prerequisite."
"Go on."
"Black Iron has to stay standing."
The channel fell silent for two seconds.
"Has Xu Yanqiu provided a schedule for the improved joint-cooling solution?"
Sheng Lan flipped through a page of records.
"Professor Xu said he could produce an improved cooling module within two weeks after we return home. At this stage, we can only make do with the temporary measure of removing the auxiliary panels."
"Then make do. Han Zheng, this isn't the time to fight. Your mission is to record data. Waltfeld is here to fight the Archangel, not you."
Han Zheng turned the optical lens back toward the Dry River Valley.
The six Bakus had already passed beyond the right edge of his field of view, continuing to press southeast.
The sand behind them trailed in six gray-yellow streaks, like claw marks carved into the desert.
Jiachen's tactical screen quietly recorded every frame of movement data.
"Deputy Officer Sheng." Han Zheng kept his voice low.
"Speak."
"Will the Archangel... hold out?"
Sheng Lan's pen paused over her memo pad for a moment.
"That isn't your concern."
Han Zheng did not ask again.
Twenty minutes later, dull booms came from the southeast of the Dry River Valley.
They were too far away. On the panoramic screen, only an orange flare could be seen rising near the horizon, followed by a second, then a third.
Jiachen automatically switched to acoustic analysis mode and delivered its assessment after a six-second delay.
Crossfire from beam weapons, accompanied by explosions from solid ammunition.
The battle had begun.
Ye Qingluan's interception report appeared on Sheng Lan's terminal.
The Archangel's starboard guns were firing at full force, and the Strike Gundam had launched to engage.
Tian Mu's voice from Unit Two tightened slightly.
"Han, the Baku formation is heading toward the Archangel. The Archangel is being forced back. If it turns to avoid Waltfeld's encirclement..."
He did not finish.
Jiachen finished for him.
On the tactical screen, the Archangel's predicted turning path was marked by a red dashed line.
The extension of that dashed line pointed directly at the East Asia Test Detachment's encampment.
Sheng Lan closed the terminal and pressed the communications key.
"Director, the Archangel has been forced to change course. If it continues along its current route, it will pass within three kilometers of our temporary encampment in six hours."
Lin Yuan's reply contained only two words.
"Do not withdraw."
Sheng Lan's pen tip hovered above the memo pad.
"Director..."
"Do not withdraw. Have Han Zheng position all three Black Iron units. Jiachen will enter full-area passive monitoring mode and record all combat data from the Strike Gundam and the Baku formation."
Sheng Lan slipped her pen back into her pocket.
"Director, what if Waltfeld's reconnaissance units find us?"
The other end of the channel was silent for three seconds.
"Then let him find us."
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