One of them would open nine out of ten MIT doors, but those were mostly uninteresting classrooms and labs. The others were special offices and storerooms.

Most students who had been around a long time had access to a similar collection, or at least knew someone like Matt. MIT had a venerable tradition of harmless breaking and entering. When he was a second-semester freshman, Matt had been taken on a midnight tour of the soft underbelly of MIT, crawling through semisecret passageways that crackled with ozone and dripped oily condensate, emerging to tiptoe through experiments in progress—look but don’t touch—room after room of million-dollar gadgetry protected only by the hackers’ code of honor. You don’t mess with somebody else’s work.

And you don’t steal. But then it wouldn’t be stealing if it was for an Institute project, would it?

He brought up a schematic on the computer and made a list of components he wouldn’t be able to just pick up in his own lab, or rather Professor Marsh’s. He knew where all of them would be, since he’d already built the thing once.

Saturday night in a blinding snowstorm. If he met anybody else, they’d be hackers on similar errands. Or janitors or security guards, neither of whom would be much of a problem. He’d guided freshmen on the tour dozens of times, and they only had to run like hell twice.

He half filled a thermos with the rest of the coffee and made two peanut butter and jelly sandwiches, and put them in his knapsack along with the computer and key ring. He emptied out a multivitamin jar and sorted through the various pills. He broke a large Ritalin in two and swallowed one half. The other he folded up into a scrap of paper and put in his shirt pocket. This would be an all-nighter.

What he really wanted to do was set up the machine with the camera and a watch, and send it off into the future. But not until he had a duplicate.

He had to smile when he imagined the look on Professor Marsh’s face when he pushed the RESET button on the duplicate. He tried to hold on to that thought as he barged out into the blowing cold.

3

It turned out to be more than an all-nighter. Hehad to sneak into fourteen different labs and storerooms before he had all the parts in his bag. In some places, he left IOU notes; in some, he assumed people wouldn’t miss the odd resistor or thermocouple.

A thin gray winter dawn was threading through the window when he gathered all the parts together at his bench. He hadn’t been able to quite match everything precisely— all the electronic and optical components had the right characteristics, but they weren’t all from the same manufacturers as before, which shouldn’t make any difference. But then the machine shouldn’t disappear, either.

He had a pine plank instead of the furniture-quality oak he’d scrounged. Surely that wouldn’t make any difference, the neutral platform. He trimmed it with a table saw to just the right dimensions, then he found the cardboard template he’d used as a guide and drilled holes in the board to position the various components. Then he took it to the chemical hood and spray painted it with two coats of glossy black enamel. It was fast-drying, supposedly, but he set a timer for a half hour and stretched out on the bench for a nap, his more or less dry boots folded for a pillow.

Waking up not too refreshed, he took the rest of the Ritalin and heated up half a 1000-ml. beaker of water for coffee. While it was coming to a boil, he set out all of the components in order next to the drilled and painted plank and then got together the tools and materials he’d need to put it all together.

This last step was the most satisfying, but also one prone to spectacularly stupid error, because of familiarity and fatigue. He got a big mug of coffee and stared at the neat array as the drug came on slowly, waking him up. He assembled the calibrator mentally, writing down the steps in sequence on a yellow pad. He studied the list for a few minutes, then rolled his sleeves up neatly and got to work.

It was a mind-set he remembered from childhood, spending hours in the meticulous construction of airplane and spaceship models, excitement holding fatigue at bay. Now, as then, after he’d soldered the last join and firmly tightened the last tiny screw, he felt a little letdown, the fatigue hovering.

He slid the fuel cell into place and tightened the contacts. Push the RESET button or not?

Had to try it. He set his watch to the stopwatch function and pressed both buttons simultaneously.

Nothing happened. Or, rather, the calibrator emitted one photon per chronon, as designed. Dr. Marsh could have this one.

A heavy lassitude flowed into him. He stretched out on the lab bench again. The thought of his soft bed at home was seductive, but the subway wouldn’t start till seven, Sunday. He checked his watch, but it was still set on stopwatch, earnestly adding up the seconds. He left it that way. Three hours and seven seconds later, he unfolded, groaning, and sat up. It was after nine, good.

He left the calibrator on the shelf and went out to face the Cambridge winter. It was overcast and bitter, in the teens or single digits. No new snow, but plenty of old. He could hear a snowblower somewhere on campus, but it obviously hadn’t made it to the Green Building. He crashed through the snow, more than knee-deep, toward the Red Line. The smell of Sunday morning coffee at Starbucks lured him in.

He put enough sugar and cream in the coffee to call it breakfast, and thought about the next stage of the experiment. The machine would be away for three days and eight hours. There would be the cell camera recording the machine’s surroundings, and he’d leave his watch in there to record the passage of time—or buy an even cheaper one that he wouldn’t mind losing.

A guinea pig. See whether something alive would be affected by the suspension of time, or whatever was going on.

An actual lab animal would be pretty complicated: cage and water and all. He thought about catching a cockroach, but actually he hadn’t seen any of them since Kara made him bring the bug man in.

Something that would survive for three days without maintenance. Something he could buy cheap or borrow . . .

A turtle. When he’d gone to the Burlington Mall with Kara to get new pillows, she’d dragged him into the pet store. They had a terrarium full of the little rascals.

They wouldn’t be open on Sunday, though. He toyed with the idea of breaking in, risking months in jail for a two-dollar turtle. No. It wasn’t MIT. The security guards would take one look at him, a shaggy drug-addled young male dressed like a street person, and shoot to kill.

The Starbucks had a phone book, though, a much-abused sheaf of dirty yellow paper, and he found the number and punched it up on his cell.

“Go to hell,” a woman’s voice said. He checked the number and no, he hadn’t called Kara by mistake. “Pardon me?”

“Oh! I’m sorry!” She laughed. “I thought you were my boyfriend. Who else would call on a Sunday morning?”

“I just . . . well, I wondered if you were open on a Sunday morning.”

“Huh-uh. I got to come in and feed and water and clean up after my babies. They don’t know it’s six feet deep out there.”

“It’s your store? You run it?”

“Yeah. Try to hire someone who’ll do this. Who has a higher IQ than the animals.”

“What if I wanted to buy something?”

There was a pause. “You suddenly need a pet on Sunday morning?”

“Not a pet, exactly.” Go with the semitruth. “I’m an MIT researcher. We need a small turtle for . . . for a metabolic experiment.”

“Well . . . you’re down at MIT now?”

“At the Starbucks, actually, right on the Red Line at Kendall Square. I could get up there in less than an hour.”

“Lots of luck.” She laughed again, a pleasant sound. “Tell you what. I’ll give you exactly an hour. Then I cover up my babies and leave.”