Death is Forever

land racing by. She tried to imagine inches of rain pouring down week after week for four months.
    “What happens to all the water?” she asked finally.
    Frowning, Cole checked his mirrors again, holding the inside mirror with his hand to reduce vibration. The clarified reflection left no doubt.
    Someone was back there, keeping pace.
    He pressed down on the accelerator harder and kept talking, not wanting Erin to get frightened. “Some of the water evaporates. Most of it just sinks in and slowly percolates to the sea through rock formations that hold water like a sponge. Limestone is one. Sandstone is another.”
    She remembered the BlackWing maps she had stared at for hours. “Weren’t those blue crosshatches on your map limestone?”
    He nodded, glanced in the rear and side mirrors, and saw no change in the relative positions of the two vehicles. The vague dust cloud far behind them had speeded up shortly after he had. Gently he eased off on the accelerator, slowing undetectably.
    “Windjana Gorge is an ancient reef,” he said. “The Oscar Range is marine limestone. Old, old reefs, and the fossils to prove it.”
    “But no water?”
    “Sometimes you get springs and seeps where the limestone beds have been fractured. The water that flows up is fresh and probably thousands of years old.”
    “What if there aren’t any springs? Does that mean the limestone doesn’t hold water?”
    “Not necessarily. When conditions on land are right, water dissolves passages in the limestone and all the runoff water goes straight underground. Eventually you can have rivers slowly flowing through solid rock. That’s how you get cave systems like Carlsbad Caverns in New Mexico.”
    “Do you think something like Carlsbad exists in the Kimberley, just waiting to be discovered like Abe’s diamonds?”
    Cole heard the excitement in Erin’s voice and tried not to smile. “The odds are against it. Caves are short-lived. Most of them don’t last any more than six million years.”
    “Is that all? Gosh, maybe we’d better drive faster.”
    He glanced at the deadpan innocence of Erin’s expression and smiled despite the sticky heat and the persistent vehicle behind them. “In human terms, caves last forever, but they’re only mayflies compared to diamonds. Those rocks wrapped around your waist might well be the oldest things on earth.”
    “What?” she asked, startled.
    “It’s a long story.” He glanced into the mirrors.
    “This is a long road,” she said, smiling.
    Her smile made him wish that they were anywhere else, so long as it was safe. Because it wasn’t safe now. The vehicle behind them had shifted speed every time Cole had. Whoever was back there didn’t want to catch up or pass.
    It might be that the traveler had unconsciously paced himself against the car ahead, or it might be something a lot less innocent. Either way, innocent or not, they were trapped. There was only one road for the next thirty klicks, and both vehicles were stuck with it.
    He stared into the mirror, then glanced quickly at Erin, afraid that she’d notice his growing distraction. He didn’t want to tell her about the tail unless he had to. Adrenaline would exhaust her even faster than the brutal climate.
    The terrain began to pitch up very subtly. Experience told him that about ten minutes ahead there would be long, rolling creases in the land. Then the road would fork. The spur would go to Windjana Gorge. The Gibb River Road would head on toward the King Leopold Ranges and an eventual dead end at the tiny settlement of Gibb River. Nearly all the Gibb traffic was to stations along the way.
    No locals went to Windjana in the buildup. Nor were there any tourists in Derby. He and Erin were so unusual that they’d been stared at on the street. Which meant that if the dust cloud turned off at Gibb, everything was fine. If the dust cloud followed the Rover to Windjana, everything was fucked.
    “Cole?”
    He glanced away from the mirror. “Hmm?”
    “How do diamonds get into volcanoes?”
    “We used to think diamonds crystallized out of molten rock as it cooled,” he said. His voice was calm, revealing none of the tension rising in him as he drove toward the Windjana spur. “But the inside of a volcano is damned hot. Diamonds would melt there like chips of ice in fresh coffee.”
    He paused and glanced aside to see if she was looking in her side-view mirror. She wasn’t. She was watching him, her beautiful green eyes wide and