Other Books by Ian Douglas

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      PROLOGUE

      8 AUGUST 2040

      Cave of Wonders, Cydonia, Mars

       1445 hours MMT

      Sound did not carry well in near vacuum, but Dr. David Alexander felt the slight, ringing vibration of each step through the insulation of his Marsuit boots. There’d been no sound within this chamber in…how long? The team’s best guess was half a million years.

      “Halfway across the catwalk,” he said, speaking into the needle mike positioned close by his lips. “Twenty meters.” Over the headset clamped down over his ears, he could hear the unsteady rasp of his own breathing, the hiss-thump of his backpack PLSS. His breath, hot and moist, fogged his helmet visor with each exhalation, a white smear immediately dissolved by the stream of cool air blowing past his face.

      “Ah, we copy that, Aladdin,” a voice crackled in his ears. “You’re looking good.”

      Aladdin. The radio handle was a last-minute joke concocted by Ed Pohl that morning, back at C-Prime. Naming this place the Cave of Wonders had been his idea, after he’d seen the first transmissions from the penetrator robot three days ago.

      It could as easily have been Ali Baba. The cavern, apparently, required a human presence to operate it, a living open, sesame to switch on power and lights and to open doors. Robots massing one hundred kilos and programmed to radiate at thirty-seven degrees—human body temperature—had failed to learn anything about the long-sealed chamber. Alexander, claiming the right as the one who’d found the cavern entrance in the first place, had volunteered to go in. He was, he estimated, a hundred meters into the vast and labyrinthine complex hollowed out beneath the Cydonian Face, and perhaps ten meters beneath the surface of the ground outside.

      “Aladdin, we’re seeing an increase in heart rate and respiration. Please check your O₂ mix.”

      “Copy.” His eyes flicked to the med and PLSS readouts mirrored above and to the right of his visor, checking that all were well in the green. Of course his heart and breathing were faster, the idiots! “O-two at six-point-three. Systems nominal. Fifteen meters.”

      “Ah, roger that, Aladdin. Watch the hyperventilation.”

      That sounded like Doc Penkov. He could imagine all of the Team members back at Cydonia Prime, crowded into the radio shack as they followed his progress. Only Devora Druzhinova and Louis Vandemeer were on the surface today, now waiting just outside the tunnel entrance in case he needed help.

      The catwalk of black metal trembled harder with his next few steps, and he stopped, gripping the pencil-thin guardrails to either side until the motion dampened itself out. His heart was pounding hard now, beneath the breastplate of his suit. At last, he was inside the Face….

      The Face…first observed on photographs transmitted to Earth late in the previous century by the Viking orbiters and subsequently confirmed by other robot spacecraft. The Face…enigma and lure, drawing scientists like David Alexander to probe its secrets, held in silence now for half a million years. Even now, with all the evidence of the ancient ruins uncovered on the Cydonian plain, with the uncanny discovery of flash-frozen and desiccated corpses of long-dead archaic Homo sapiens on Mars, there were some who yet thought the two-kilometer-long mesa’s vague and sandblasted resemblance to a human face to be the product of chance and human psychology.

      The discovery of the Cave of Wonders had all but put to