The story that stuck in Anna's mind was of a man who suffered from a crippling case of muscular dystrophy. In his late twenties, he'd been wheelchair bound over half his life. His greatest fear was that his house would catch fire. If he couldn't get to his wheelchair, he would burn to death.

During the trip this man was unable to carry canoes or gear on the many rough portages. But he chose not to be a burden to the others. He discovered an untapped talent. Clad in protective clothes, he crawled and inched and slithered, dragging his legs over fallen logs, across rocky beaches, and through weed-choked ravines.

By the end of his sojourn in the wilderness, his fear of burning to death in his own home was gone. "I can crawl out," he said. "I never thought of it. Shoot, I could crawl the six miles to the fire station if I had to." He'd regained some of his lost mobility.

The guy would have made a heck of a caver.

They'd been traveling ninety minutes, had gone less than three quarters of a mile, and had ventured into the earth four hundred feet, when they came to the North Rift.

The rift was a great crack running northwest to southeast, splitting the known world of the cave as a cleaver might halve a melon. Pointing with his light, Oscar picked out a hand line, threaded his rack, and descended. At the T-shaped junction where passage met rift, the cut was only fifteen feet deep. Moments later he was climbing up the far side. A cringing, spine-scraping crawl later they emerged next to a huge fissure. The Rift gone mad.

"Jesus," Anna breathed as she cleared the last tumble of rock. Iverson was seated on a square block of breakdown the size of a refrigerator. The stone was sheared as neatly as if a gargantuan mason had done it with a chisel. Pieces, varying in size, clung to the edge of the precipice. She scratched her way up to sit gingerly beside Oscar, her hands hooked on the back of their limestone couch lest the pull of the deeps should suck her down. "Shouldn't there be a sign here that reads 'Beyond This Point Be Monsters'?"

"Left goes up to the North Rift," Iverson said. "Right is the main route to the rest of the cave. We go right."

The word "impassable" came to mind. Above, stone vanished into the gloom. Blocks the size of rooms jutted from the walls. Where she and Iverson sat, it was about thirty feet wide, the far side smooth, vertical, offering nothing in the way of an inducement to cross.

"Right?" Anna said.

"Right."

"How?"

Iverson smiled. "There." He painted a curved surface of rock above her with his light. The wall of the rift bulged slightly and bent around in a southwesterly direction. On closer examination, Anna could see where a rope had been strung. The trail-using the term loosely-was suspended along the wall eight or ten feet above where they sat. Pitons, bolts were frowned upon in wild caves. Driving these man-made anchors into living stone left scars. The rope above them made use of a motley assortment of natural anchors: BFRs, Big Fucking Rocks; jug handles, natural holes in the rock; and stalagmites.

Below, the rift fell away in a rugged canyon. Light served only to beckon forth the shadows and veil secrets. It struck her as odd that all of it-this tremendous gorge, the seeps and falls and spires-could continue to exist in the total absence of light and life. Like the philosophical tree falling in the theoretical forest, with no one to hear, not so much as a gnat or a dung beetle to take note, did it really exist? Apparently it did. "How deep?" she asked.

"Here? Maybe one hundred twenty-five feet or so. It varies, of course. Nobody's ever really done much exploring down there."

As far as Anna was concerned, that left it wide open as a habitat for impossible creatures from the underworld. It was no mystery why the ancients peopled caves with evil spirits and placed their hells deep within the earth.

"Definitely a No Falling Zone," Iverson said mildly.

Anna turned her light on his face. He was smiling with what looked to her like genuine delight. "You really are a creepy person, you know that, don't you?"

Holden Tillman eased up beside them and swung his legs over the edge. Anna kept all her appendages on solid ground, her legs folded neatly under her, tailor-fashion.

"So," Holden said, uncapping his water bottle and pausing for a long pull. Anna followed suit, checking first to reassure herself there wasn't a "P" scrawled on the cap.

"Freak-Out Traverse," Holden said, and waved toward the roped cliff face with his water bottle.

"Gee, why do you think they call it that?" Anna asked.

Holden didn't seem to notice the sarcasm. "Interesting story," he said. "See below the rope there? That great, big, old, solid-looking poke-outance, just exactly the right size to wrap your arms around and hang on to for dear life?"

He traced the rock outcrop he described with a golden finger of lamplight. It was the obvious place to make the traverse. Anna had wondered about the trail being set so high above the starting point.

"We got here. Me and a caver named Ron. I, being the gentleman that I am, insisted Ron have the first crack at it. 'Oh, no,' he said. 'After you, my dear Holden.' 'I wouldn't dream of it. After you,' says me. So he goes first. Ron gets to that big, old, friendly rock and spreadeagles himself across it like a love-struck starfish. And that sucker starts to move. The thing is on ball bearings. Hence 'Freak Out Traverse.' I let Ron name it. I'm just naturally generous that way."

Even in the wandering half-light, Anna noted the twinkle in his eyes.

"Everybody rested and rejuvenated?" Iverson asked.

A sheer curtain of panic, like heat rising from the desert, quivered behind Anna's breastbone; panic not at the traverse but at going on instead of turning back. Gideon, the horse she'd ridden on backcountry patrol when she was a ranger at Guadalupe, and she had this discussion at every fork in the trail, Anna insisting they go on, Gideon determined to take every opportunity to go back to the barn.

Rest stops were going to be bad news.

"Ready," she said, and was the first to get to her feet. Movement was good, work even better. She felt herself almost looking forward to Freak-Out. That should take up every shred of her thought processes for a few minutes.

After Freak-Out the going got somewhat easier. Though a good deal of effort went into climbing on, around, and under the blocks, little of it was heart-in-mouth stuff.

Shoving her hands in cracks, her face in the dirt, reaching into darkness, squeezing through the narrow ways, Anna came to appreciate the sterility of the cave environment: no spiders, grubs, scorpions, rattlesnakes, wasps, tarantulas, ants, or centipedes. She burrowed and barged her way through with more or less complete confidence that, as predators went, she was pretty much alone. Given the forced intimacy with blind crevices and dank hidey-holes, this was definitely a plus. This far in there wasn't even any evidence of that benign resident, the cave cricket. For the first three or four hundred yards she had seen a few of the harmless, spectral insects, but cave crickets found their food on the surface or in the twilight zone where the outer world reached within. They seldom wandered more than an easy cricket commute from the terrestrial world.

Partway down the North Rift, half an hour's travel and not quite a hundred yards as the crow flies-should a crow choose such a batlike endeavor-Iverson stopped again, perched this time on a narrow ledge, his lamp extinguished. Lest he startle Anna and make her lose her footing, he announced himself shortly before her light strayed across his aerie. "I'm here," he said softly.

Anna squawked, her heart leaping so forcefully it felt as if it pounded against the rock she embraced. "Don't do that," she said when breath returned and she'd found a stable roosting place.