She sank to her knees, probing at the snow around the runners to make sure nothing had fallen out. She couldn't feel anything – the bulge of the duffel bag seemed to have sealed the breach in the hutch. She risked a short walk uphill, heading directly toward the spur, but all she saw was a tapering strip of wood and a single, palm-sized lump of black rock. When she was satisfied that she wouldn't find anything else, she staggered back downhill. She turned the sledge around and continued along the channel of the ice stream.

It would be more than a month before she discovered exactly what she had left behind on the slope and the full consequences of her accident became clear to her.

That night, after she sealed the hole in the sledge with a strip of plywood, she found herself replaying a certain incident from her childhood. It came to her while she was pitching the tent, whirling and condensing in her memory like a tiny runaway planet, so that by the time she fastened the door it had returned to her in all its particulars. The incident was an inconsequential one – of no importance whatsoever, really. But then most of the things she remembered, most of the things anybody remembered, were of no natural importance – were they? – and that never stopped them from rising into the light.

In her memory she was seven years old, and her mother had just taken her out of school for a dentist's appointment. Only that morning, her mother had said, "Now don't let me forget, we have to get you to the dentist by two-thirty. What time do we have to get you to the dentist by?" and Laura had answered, "Two-thirty o'clock," and her mother had said, "There's no o'clock to it, hon. It's just two-thirty," which was why she remembered what time the appointment was supposed to be.

She buckled herself into the car seat and waited for her mother to finish talking to the woman with the orange vest who stood by the front door in the afternoons. Laura and her friends had made an I-Spy game out of the orange vests: whoever could spot the most was the winner. She had noticed that there were always more of them on the days when the sirens went off than on the days when they didn't.

Only recently had she grown tall enough to see out the window of the car without rising onto her knees. As her mother climbed into the driver's seat and the engine made the coughing and shredding noise it always made when it was turning over, she noticed an unusual thing. On the roof of the house across the street was something she had never seen before. It looked like a spinning silver pumpkin trapped inside a metal grate.

"What's that?" she asked her mother. "What's what?"

"That thing," she said, pointing. "The silver ball on that roof."

"Oh. They have those all over the place. It's a – " Laura watched the motions of doubt appear in her mother's face as she began to answer the question and then realized she didn't have the words. "You know, I'm not sure what it's called. It's part of the house's circulation system. I can tell you that."

Earlier in the week, Laura had watched a TV program about the body's circulation system. She remembered the image of a man whose skin peeled away to show his blood pumping through him, a loose basketry of red and blue vessels surrounding a large, throbbing heart. The connection seemed hazy to her. "A circulation system like for blood?" she was about to ask, when another car came hurtling around the corner of the parking lot, driving backward, and punched into the edge of their front bumper.

The car scraped along their driver's-side door, not grinding to a stop until it had lined up with them window for window, rearview mirror for rearview mirror, pressed against them as though it were backing into a parking space. Laura saw the driver pause and shake her head before she reached over to apply the emergency brake.

Softly, as though she were simply commenting on the weather, her mother said, "Well, goddamn it." Her face usually had a strange, almost strict expression when she was driving, but for the moment, at least, it was completely empty. She was one of those people who truly became beautiful only when they showed no sign of thought or feeling on their faces, like bright, blank flowers unfolding their petals in the sun. Later, after Laura had grown up and moved away, that was how she would remember her mother – as a woman caught in a lovely thoughtlessness.

"Are you okay?" her mother asked her. Laura said that she was fine.

Her mother lowered her window and motioned for the woman in the other car to do the same. The woman's window sank away, taking a dim reflection of them with it. She said, "I'm having an unbelievably rotten day."

"So am I," Laura's mother said. "At least now I am."

"Like you wouldn't believe," the woman said.

Laura's mother began working a muscle in her jaw, but almost immediately she became plain again. "Listen, maybe you should pull forward and let me open my door."

"I can't," the woman said. "That's one of the problems."

"What do you mean, that's one of the problems?"

"There's something wrong with my car. It won't pull forward. It will only go in reverse. That and my kid left his books at home, and the stationery store was closed."

"Then maybe you should back up and let me open my door," Laura's mother said.

"Oh. Okay." The woman released her brake and inched backward, scraping along the side panel of the car. She slowly drifted out of contact with them. She switched her motor off and rested her forehead on the padded arch of the steering wheel, lacing her fingers together behind her neck. It was then that Laura heard her moan – a low, soft animal sound that seemed to swell up from somewhere deep inside her.

"The cow goes moo," Laura said.

"Quiet, honey."

Her mother unlatched the door. It made a creaking and buckling sound as it swiveled around the crimp, and almost at once, the car's warning bell began to ding. The bell usually came on when the door was opened by even so much as a crack, though sometimes it didn't. It was something that Laura found impossible to predict.

"Wait here," her mother told her. She shut the door and strode over to the other car. Laura could hear what she was saying through the open window. "Do you want to call the police, or do you want me to?" After a few seconds she repeated herself. "Hello? Do you want to call the police, or should I?"

"You're not supposed to move a person with a broken bone. You're supposed to wait for the ambulance," the woman answered.

"Did you break something?"

She shook her head. "I was talking about the car."

"Oh, for crying out – " Laura's mother frowned and cocked her hand in the air. Laura thought that she was going to cuff the woman, but she allowed the gesture to go slack and in the end only slapped the roof of her car lightly with her palm. The noise was still loud enough to make the woman jump in her seat.

"Look, if your car doesn't work, you shouldn't be driving it in the first place."

"It was working just fine when I left the house. Then the stationery store wasn't open, and I dropped Eric's books off, and when I came back outside, it would only go backward." The woman leaned over to pick something up from the floorboard and she straightened back up with a phone to her ear. She pressed a few buttons.

"And to top it all off," she said after a moment, "it looks like my phone is dead."

"I'll make the call," Laura's mother told her. "You wait right here. Don't go driving off anywhere. Just… wait." She returned to the car, sat down, and fished the telephone out of her purse. Laura listened to her telling the police operator all about the accident: who had hit whom, where they were located, how many people were involved. "No, no injuries," she said. "But the other driver seems a bit… off, I guess you could say."