“Dammit, Mauricio! Shut the hell up and save your breath.”

  Filson was doubting the wisdom of bringing the Chilean engineer turned soldier along. He wanted immediate access to the guy’s knowledge of the Metro in case they got stuck or confused. But he was slow. And since he was at the head of the column, that made everyone slow.

  Not that the chunky old man wasn’t trying. He was. He just didn’t have the stamina or strength. He might have been able to keep up on a flat road march. But more than a year of war on Santiago’s surface had been hard on the underground Metro line, turning it into a dark obstacle course. Stretches of knee-high water, fallen steel beams, and large segments of concrete with exposed and rusting rebar made for slow going, even for the agile Maulers and powerful Centaurs.

  What made it worse, though, was Mauricio’s inability to pass any curiosity of his creation without commentary.

  “I spent a month calculating the loads on those buttresses.” Or, “That is one of the north-running sewer access lines we had to integrate to. It passes under the Mapocho.” Or, “That’s a rainwater runoff channel. Goes all the way to the ocean. I had a full team assigned to it.”

  For the past few minutes, despite nearly falling over from a heart attack, Mauricio had pointed at a grimy opening in the tunnel wall and described, in great detail, all the sewer passageways that intersected the spur line. “The passageways provide maintenance access to the meter-wide sewer lines running north. Some of them run north for tens of kilometers and are over a hundred years old!”

  Filson was over it. He raised his right hand in a fist and came to a halt.

  The entire column—a dozen Centaurs, forty-eight Lobos, and fifty-seven Maulers—stopped on their next footfall as if they were all linked by the same nervous system. Before Filson had turned back to look at Mauricio, every soldier, human and robot, had taken a knee or was prone. The only noises in the subway tunnel were the whine and buzz of aerial scouting drones.

  This tale has been unlawfully lifted from Royal Road; report any instances of this story if found elsewhere.

  The small drones had been all the way to the breach site and back several times. All clear so far. So, Filson was pressing hard to cover the remaining kilometer as fast as possible.

  Mauricio couldn’t keep up.

  “Hatch!”

  “Yes, sir!” the M-47 said, standing next to Filson. Mauricio was bent over, panting, hands on his knees.

  “I want one of your soldiers to carry LT Rivas.”

  Mauricio shook his head, but didn’t lift it. “No, sir. That is not—”

  “Not talking to you, Mauricio.”

  Another M-47 soldierbot appeared out of the shadows. Walking over to Mauricio, it scooped him up in its powerful metal arms.

  In addition to designing the M-47s so that Centaurs could jack into and pilot the soldierbots remotely, Northrop Grumman had tried something new with their command hierarchy. The Prime, Hatch in this case, attached itself to the Centaur commander’s side, shadowing them throughout the entire mission. In addition to the benefits of simple physical proximity, a network link was formed between the Centaur commander’s onboard tactical AI and the Prime M-47.

  The Prime then continuously cascaded instructions and intel to its subordinate M-47s on their own encrypted, frequency-hopping radio network. They also fed their situation and status up to the Centaur commander’s tactical AI. An indispensable link in battlefield communication, the Prime was like a high-speed router that could shoot things.

  This was the capability Filson liked about them most—their ability to instantly share intel, orders, and situational awareness. Once one of them knew something, all the others knew it a nanosecond later. Filson found that if he could get them to understand orders and objectives, they were effective fighting partners.

  Problems could arise when the situation changed rapidly, necessitating new orders. Their decision engines were optimized for execution, not tactical innovation. There had been some high-profile failures in combat, where the M-47s froze, awaiting clarification. Filson attributed those occasions to the human commanders being slow to react. M-47s had never frozen on him. How hard is it to say, “Kill all those guys,” anyway?

  Filson tried not to chuckle at the sight of the portly Chilean officer, grimacing with embarrassment in the arms of the big robot like a bride being carried over the threshold.

  He thought he saw relief in Mauricio’s eyes also.

  “I want him glued to my side,” Filson told Hatch.

  “Yes, sir.”

  Raising his arm, Filson turned back to the darkness ahead and stepped forward. The column followed.

  Checking his watch, Filson started jogging.