"Of course. Things will proceed about as we intended. With the primary purpose of scientific exploration. But we'll cut the parties to ten men each to risk less personnel. One party with specially shielded space suits and tractors will invade the sunward hemisphere, while you folks will go the other way." * * * * * Within an hour, under Schmidt's able command, Rick and his other companions were moving along the highway toward the shadowy eastern hills, with two tractors fitted with pressurized cabins. Rick and two other men, Lattimer and Finden, rode atop the lead vehicle as lookouts. Rick thought of how flexible a Survey Service guy had to be. Here their intended work was to learn about Mercury--to dig, even, into its crust, searching out its mineral wealth and learning its history, even back far beyond the rivalry of the Martians and Xians. A steaming, fast-spinning little world, it must have been once. And of course its now dubious value to modern civilization and economics must be judged. But now another duty was added--something of criminal detection! There was suspicion without proof. Doubt that might be groundless, almost. Or that might point to a deadly unknown. What must be Fane's tracks in the dust, were visible in one place for about a mile, along the hard-surfaced road. But then they vanished among the rocks. And what sense was there to try to hunt him out of the hills? Schmidt gave no such order. And Rick realized fully, then, that it was not so important to find Fane himself, but to learn what fabulous mystery it was that had made him hurry into this wilderness alone. Something tremendous must be at stake. Miles were covered swiftly at first, making the sliver of sun sink from view to the rear. But one pale wing of the solar corona--a reminder, here, of the final sunset so long ago--still projected above the horizon, providing ghostly illumination. There was little talk, but Rick Mills felt as if he was invading some immense and haunted cellar, covering half a planet. For young Finden to photograph, there were domed structures, vast buildings that might have been factories, huge slag heaps from mines, even the still standing trunks of trees, that had been perhaps developed from Martian stock. Thicker and thicker layers of frost and frozen air were over everything. And scattered along the road were the scars and wreckage of violence. Here, wood had been blackened by fire. Here, dug in the ground, had been a fortified strong point and supply-dump, full of toppled cylinders. Here there were dried-out, blackened corpses. The Martians, their many tentacles stiffened to the consistency of old wood, looked like charred tree-stumps. The Xians, with but four boneless limbs, were like deflated sacks of old leather.