Inside his older machine, he struggled to keep up with the new-model cymeks as they thundered over the rocky ground. He worked his arms, linked to the controls, but the walker limbs were not analogous, and he occasionally became tangled, feeling clumsy. His other machines were so graceful.

Practicing their fighting abilities, they grappled with one another to test strength and reflexes, warrior arm against warrior arm. He identified each of them by unique light panels on their bodies. One walker, operated by the brain of the female Xinshop, sprang to a high outcropping, but failed to gain sufficient height. Before she could tumble down, however, rockets erupted from the body’s rear thrusters, lifting the new cymek to safety on top of the rocks. Once stabilized, Xinshop raised a pair of grappling arms as if in triumph.

Ptolemy liked Xinshop’s willingness to serve. She had been among the first of the failed Navigators to embrace her new possibilities as a cymek. Each time he spoke with her, he envisioned what Xinshop used to look like before he’d met her, when she had been a radiant young woman volunteering for the VenHold Spacing Fleet. Sometimes Ptolemy even imagined that they might be together as a couple, both of them cymeks. But before that happened, he had a lot of work to do getting his mechanized force together, refining systems. That was his priority.

He also liked the reemerging personality of Yabido Onel, who was bounding across the rugged landscape in the foreground. For a long time Yabido had refused to say much through the speakerpatch, except for his desire to die because he had failed as a Navigator candidate. But after Ptolemy showed him what he could achieve as a cymek, he had felt renewed hope and determination, which expressed itself as bright energy patterns in his brain.

Ptolemy could still see the glow of research domes. Although his expanding Titan project had siphoned some of Denali’s most talented engineers and support staff, Administrator Noffe was still developing weaponry in independent programs, such as scrambler pulses that could boil human brains, in much the way the Sorceresses of Rossak had killed the old cymeks. One research team created small mechanical “crickets” that could skitter into enemy ships and ignite volatile fuel storage chambers.

Ptolemy’s fellow researchers had their own reasons to dislike the fanatics, but he believed his program would be the one that guaranteed victory against Manford Torondo. A marching horde of new Titans powered by proto-Navigator brains would strike fear into any populace.

As he trudged along in his repaired walker, far from the research domes, Ptolemy noticed two amber warning lights on the control board inside the cab. His life-support systems were losing power due to a leak in a coupling, eroded by the caustic atmosphere. And he was trapped in his small chamber.

He ran an estimate and realized that he barely had time to hurry back to the shielded complex. No safety margin.

Without delay, he worked the controls and turned his walker around while transmitting a distress signal to his Titans. With a jittering gait, he tried to hobble across the landscape, but he was too anxious, which made him uncoordinated. His arms twitched inside the linkages, the thoughtrode signals scrambled.

He didn’t want to die out here, not with his work incomplete.

A hose snapped and began to leak fuel onto the ground outside. Warning lights flashed across the cab controls. Now Ptolemy realized he could not possibly make it back. Unable to control the mechanical legs, he stumbled, and went down.

Moments later, two burly Titans — the pair of mercenaries Hok Evander and Adem Garl — appeared on either side and grasped his smaller cymek body with their mechanical claws. They raised his walker form off the ground like two metal crabs lifting their little brother. With an eerily coordinated gait, the Navigator cymeks bounded across the rugged rocks toward the glowing domes.

Another leak, and Ptolemy’s life-support system failed entirely. The caustic gases seeping into the systems would eat away more seals.

His comm system was still active, and he transmitted an emergency alert to the base. The rest of the Navigator Titans rushed back toward the facility like a coordinated rescue team, so that when Ptolemy arrived at the main dome’s airlock door, they could assist.

Through the swirling mists, Ptolemy made out the dome just ahead, but he could also smell the acrid vapors leaking into the life-support cab, beginning to poison him. The chamber integrity had failed in five separate areas. His eyes burned from the acid fumes, but somehow (delirium?) it didn’t feel as painful as the burning tears that had streamed down his face after he saw Dr. Elchan roasted alive in the lab.

Having received Ptolemy’s emergency transmission, Administrator Noffe appeared on the screen. “Ready to receive you. You’re going to be safe.”

“It’ll be close.” Ptolemy coughed, and each breath seared like heated glass dust washed down with acid. He coughed again, and a splatter of blood appeared on the control screen in front of his face.

Alarmed, Administrator Noffe shouted commands to the two cymeks carrying Ptolemy’s walker. They hauled him to the wide-open door of the hangar dome and roughly tossed the twitching, failing walker body inside. Using nimble claw hands, they operated the airlock controls.

Sealed in his cab, Ptolemy coughed uncontrollably. He breathed in a blistering-hot chemical mist. With a roar of loud wind, the air exchangers inside the dome began to suck away the contaminated atmosphere, venting it outside. Even before the green light winked on, Ptolemy disengaged the cab’s hatch and popped it open. He couldn’t wait any longer. How could the air within the hangar dome be deadlier than what he was struggling to breathe inside the life-support capsule? He yanked his arms free from the control linkages, crawled out of the cab, and collapsed onto the cold metal floor, retching, gasping, and coughing in a raw throat.

Thankfully, each breath felt a little cleaner than the previous one. Wind rushed around him as fresh oxygen poured into the enclosed area, but his lungs seemed to be filled with caustic blood.

Finally, a smaller airlock from the interior tube opened, and a frantic Noffe ran toward him. “Doctors are on their way.” He bent next to Ptolemy, helping him to his feet.

Ptolemy could barely see through his burning eyes, but he didn’t think he was severely injured. Or maybe he was deluding himself. “That wouldn’t have happened if I were a cymek.”

“It wouldn’t have happened if you were more careful,” Noffe retorted. “You shouldn’t have gone so far in an old walker like that.”

Somehow Ptolemy managed to smile, grating out his words. “Did you see … the Navigator walkers respond? Analyzed the emergency … rescued me. Passed the first test admirably.”

“Yes, they performed better than you did. We almost lost you!”

More thoughts were forming in Ptolemy’s head. “Directeur Venport needs to know how competent the new Titans are. Even this hazardous environment is not the most extreme place in which our cymeks could find themselves fighting.”

He kept talking even as medical personnel busily checked him over. They placed a mask on his face and dispensed some kind of analgesic mist into his lungs. Before long, Ptolemy could breathe better, and he pulled the mask aside, continuing to chatter to Noffe. “We have to conduct a more dramatic test for Directeur Venport — and I’ve thought of just the place to do it. We will take them to Arrakis.”

“You should rest and heal first,” Noffe said. “I’m worried about you.”

“I’m worried about other things — I can rest while I make the important arrangements.”