They squeezed cold water into their mouths and Sean removed his helmet and they unfolded the map between them.

“That way,” she said, and he looked up the narrow gravel road she indicated and shook his head. “That’s not right.” They promised to keep to the paved roads, the county roads, he said, and she looked at him: his red, serious face and the high, greasy bird crest of hair his helmet had styled. Hard to remember sometimes he was fifteen and not twelve, not ten, not seven.

She checked her heart and it was fast just standing still. Their altitude was 9,456 feet.

“Dudley,” she said, jamming her bottle back into the pack. “Did you rent a mountain bike so you could go tooling around on county roads?”

THE SUN HAD SPILLED into the valley, and a yellow blade of it opened a seam in the drapes and fell across the bed and across the eyes of the man who lay there sleeping. After a moment, the man turned away from the light and blinked the alarm clock into focus: 7:15.

A motel room. Colorado. To his right sat the other bed, empty and unmade.

In the bathroom, on the counter, the boy’s toothbrush lay in its puddle. The man, whose name was Grant Courtland, splashed and dried his face and returned to the room and parted the drapes. The sky was a pale early blue, a few thin clouds skimming the peaks. A beauty hard to believe in. A postcard. Some far-off bird rode the thermals, hovering there for the longest time before suddenly diving, bullet-shaped, into the trees. He watched to see if it would return to the sky but it didn’t.

He wasn’t sure where his kids were, geographically. It might be that near mountain there, those trees, which looked so close. The night before, they’d all bent over the maps, but Grant had not looked closely; it was their adventure to plan and carry out. In a few weeks Caitlin would begin college back in Wisconsin, on scholarship for track-and-field, and the mountains had been her idea, her choice, a graduation gift.

College. Already.

He stared into the distance until he thought he saw something—a wink of chrome, a flash of white running shoes. But there was nothing, of course, only the green and more green of the pines.

He picked up his cell phone and pressed a series of keys but then hesitated, his thumb hovering over the send button. The dream he’d been having came back to him—partially: a woman’s cool, exploring hand, that was all, but Lord.

He set down the phone and stared at it. After a minute he pulled on a pair of jeans, a T-shirt, and stepped barefoot into the adjoining room.

THE PATH GREW NARROWER, less a gravel road now than a kind of gully snaking up the mountain, and finally there was no gravel and no path but only this bald jawbone of rounded stones, like the dry bed of a seasonal stream shaped, year after year, by water’s only thought, which was to go down, always down, and never up.

“This isn’t right,” Sean yelled up the gully.

Ahead of him she kept going, leaping stone to stone like a goat.

He struggled on, wheezing, his body quaking and his jaw jibbering on its hinges until at last he said, “Fuck this,” and let the bike jolt to a stop, then let it fall to the stones as he staggered away.

“Caitlin!” he yelled.

He felt enormous and weightless, both. His legs took an unexpected step. Some flying thing struck his helmet, shrilled in the vents and sped away. “Bitch,” he said.

He picked up the bike and began fighting it over the stones, but in another moment he was attacked again—something under the pack now, buzzing against his back, and he dropped the bike and began to twist from the straps before he understood it was a phone, and by the time he had the pack off and the phone in his hand the buzzing had stopped. He watched the little window for the new message alert, but there was none. He checked his own phone, then dropped both phones back into the pack.

Then he picked hers out again. Stood a minute with the ruby heft of it in his hand, looked up the gully again—and then sat on a stone and punched up her text messages and read them. The most interesting thing was the names: Colby. Allison. Natalie. Amber. Lean, athletic girls who arrived in baggy shorts and tight, chesty tops to drink his Diet Cokes and stomp barefooted up and down the stairs. Girls who left impressions in the furniture and their scents in cushions and creases. Girls of constant texting and laughing and talking—always talking. The time he crouched outside the basement window and heard Allison Chow tell the other girls about her boyfriend’s big thing almost choking her. The time he walked in on Colby Wilson in the bathroom, bare-thighed on the toilet. Track shorts pushed to the knees.

Nice knock, tubs.

HE WAS CLOSER TO the top of the gully than he knew and when he reached it he found a road, another steep blacktop like the one they’d first been on. Or the same one. He found a sign that said CO RD. 153 and he found the sun on his hot neck and he found the silent pines and that was all. Uproad the blacktop made a right hook out of sight, and downroad it dropped away like a cliff. All of him, his every cell, wanted to go that way—down: the speed and the breeze and the long free ride on the back of gravity. But she wouldn’t do that, she wouldn’t go down, God damn her, and he turned the bike and stood on the pedals and began once more to climb.

He’d not gone far when something burst from the trees, so near and terrible he howled and leapt from the bike. It only lasted a moment before he heard that donkey-laugh of hers, and the blood came rushing to his face.

“God damn you,” he said.

“Oh God, Dudley, you should’ve seen your face!”

He lifted the bike from the blacktop.

“I never knew you could move so fast!” she said.

“I never knew you could be such a cunt,” he said.

She stopped laughing. And into that new silence dropped a man’s voice—from nowhere. From everywhere. In a moment it broke decidedly over the rise below them and with it came two figures, helmeted and hunched over their bikes, a man and a woman. The man stopped talking when he saw them, and he and the woman came on in winded silence, their faces uplifted and bright. The woman was younger than the man, she might’ve been Caitlin’s age, and she gave Sean a smile. One of the man’s lower legs was not a real leg but a black post locked into a special pedal, so that it was hard to say where the bike ended and the man began. He said Howdy and Sean said Howdy back. When they’d rounded the bend and were gone again, Caitlin said:

“What did you call me?”

Her face was burning. So was his.

“Christ, Caitlin. I was looking for you. We were supposed to keep an eye on each other.”

She regarded him darkly. Then she looked away and shook her head. She adjusted the band at the root of her ponytail and came forward and he flinched, and she told him she did have her eye on him, she knew exactly where he was the whole time. What kind of person did he think she was?

BOTH BEDS IN THE adjoining room were empty and unmade, their layers cast off like torments. The room, which had been so cold when the girls went to bed, was now hot and reeking faintly of perfume and sweat. Grant went to see that the heating unit was off and then crossed to the small staging area outside the bathroom where the two suitcases lay open on the racks, their insides distinguished at a glance by the colors and cuts of underthings, bras and panties.

The bathroom door was ajar, steam playing in the gap. The rasp of a toothbrush. He pushed at the door and there she stood in the steam, wrapped in a white towel, going patiently at her teeth. She might have been twenty again, in that towel. College days. Her little apartment on Fairchild over the bakery ovens. Winter mornings in bed with the smell of her, the smell of baking bread. She’d had a twin sister named Faith who drowned when they were sixteen and this somehow fascinated him. He was reading books then, literature, poetry. Then came pregnancy, bills, a baby. He went to work for a builder and she stayed in school, sometimes taking the baby with her to class when Mrs. Turgeon was sick. The baby eighteen, now. A young woman. Going to college herself. Fast as the wind and his father’s heart pounding each time she ran, My God look at her, my God don’t let her fall.