"Don't worry," said Drescher, grinning. "I'm just kidding. Figured I deserved to give you a fright after what you did to me all those years ago." But he did reach down and use a couple of swipes of his index finger to erase the last few lines of the transcript from the flatsie.

"Good luck, Mr. Procopides. Like I said, just be careful. For billions of people, the future turned out unlike what their visions portrayed. I shouldn't have to tell you this, you being a scientist and all, but there really is no good reason to think that your vision is going to be the one that actually comes true."

Theo used his cellular phone to call his car, and when it arrived, he got back in.

Drescher was doubtless right. Theo felt embarrassed about his panic attack; probably a bad dream the night before, coupled with anxiety about the upcoming replication, had brought it on. He tried to relax, looking out at the countryside as his car drove him back to the LHC control center. The tour bus was still there. It made him a bit nostalgic. Globus Gateway buses were seen all over Western Europe, of course. He'd never taken one of their tours himself, but as a horny teenager he and a couple of his friends had always watched for them in July and August. North American girls, looking for a summer of excitement, often traveled in such things; Theo had enjoyed more than one romantic evening with an American schoolgirl during his teenage years.

The pleasant memory faded to sadness, though; he was thinking of home, of Athens. He'd only been back twice since Dim's funeral. Why hadn't he made more time for his parents? Theo let his car find a vacant spot. He got out and headed into the LHC control center.

"Oh, Theo," said Jake Horowitz, coming at him from the other end of the mosaic-lined corridor. "I've been trying to get hold of you. I called your car but it said you'd been arrested or something."

"Funny car," said Theo. "Actually, I was just visiting — visiting someone I thought was an old friend."

"There's a problem with the LHC that Jiggs doesn't know how to fix."

"Oh?"

"Yeah, something with one of the cryostat clusters — number four-forty, in octant three."

Theo frowned. It had been years since the LHC had been cranked up to full power. Jiggs, all of thirty-four, was head of the maintenance division; he'd never actually seen the collider used at 14-TeV levels.

Theo nodded; cryostat controls were notoriously finicky. "I'll go have a look." In the old days, when CERN had a staff of three thousand, Theo never would have gone down into the LHC tunnel alone, but with his current skeleton crew, it seemed the best way to apportion his limited manpower, and, well, it was probably the safest place to be: sure, a crazy person might make it onto CERN's campus, looking to shoot Theo, but doubtless such an intruder would be stopped long before he could get down into the tunnel. Besides, no one but Jake and Jiggs — both of whom he trusted completely — would even know that he was down there.

Theo took the elevator to the minus-one-hundred-meter level. The air in the particle-accelerator tunnel was humid and warm, and smelled of machine oil and ozone. The light was dim — a bluish white from overhead fluorescents punctuated at regular intervals by yellow emergency lamps mounted on the walls. The throbbing of equipment, the hum of air pumps, and the clack of Theo's heels against the concrete floor all echoed loudly. In cross-section, the tunnel was circular, except for the flat floor, and its diameter varied between 3.8 and 5.5 meters.

As he'd often done before, Theo Procopides looked down the tunnel in one direction then turned and looked in the opposite direction. It wasn't quite straight. He could see along it for a great distance, but eventually the walls curved away.

Hanging from the tunnel roof was the I-beam track for the monorail, and, hanging from that, the monorail itself; Jiggs had left it parked here. The monorail consisted of a cab big enough to hold a single person, three small cars each designed for cargo rather than passengers, and a second cab, facing the opposite direction, capping the end. The cargo cars weren't much more than hanging baskets made of metal painted peacock-blue. Each cab was an open, orange frame with headlights mounted above its sloping windscreen and a wide rubber bumper mounted below. The windscreens sloped at a sharp angle.

The driver had to sit with his legs out in front of him; the cab wasn't tall enough to accommodate a normally seated person. The name ORNEX — the manufacturer of the monorail — was emblazoned across the cab's front. To either side of the name were small red reflectors, and below it was a wide strip with black-and-yellow safety markings; they wanted to be absolutely sure the cabs would be visible in the dim tunnel. The monorail had been upgraded in 2020; it could manage about sixty kilometers an hour now, meaning it could circumnavigate the tunnel in under thirty minutes.

Theo got a tool box from one of the supply lockers in the staging area, put on his yellow hard hat — even though he rarely went down into the tunnel, he was senior enough that he'd been given his own personal hat. He placed the tool box in one of the cargo cars, clambered into the cab that was facing in the direction he wanted to go — clockwise — and set the train in motion, whirring away into the darkness.

Detective Helmut Drescher tried to get on with his work; he had seven open case files to dig through, and Capitaine Lavoisier had been demanding he make some more progress. But Moot's mind kept turning back to the plight of Theo Procopides. The guy had seemed nice enough; he wished he could have helped him. He'd looked to be in good shape, too, for a man who must have been almost fifty. Moot found the flatsie that had recorded their earlier conversation; the biographical-data box about Theo was still displayed. Born 2 March 1982 — so that would make him forty-eight. Pretty old to be a boxer — besides, he had the wrong build for it. Maybe in whatever alternative reality the visions had shown he'd been a coach or a referee, rather than an actual fighter. But no — that didn't seem right. Moot didn't have the business card with him that Theo had given him two decades ago, although he had saved it through all intervening years, and had looked at it occasionally: it had clearly said CERN on it. So, if he was already a physicist before the visions took place in 2009, it seemed unlikely that he'd switch to a career in sports. But Moot remembered his own vision vividly: the man in the smock — the medical examiner, he knew now — had clearly said that Procopides was killed in the ring, and—

In the ring.

What was it Procopides had said earlier today? You must have heard of it. There's a tunnel at CERN twenty-seven kilometers in circumference buried a hundred meters down; a giant ring, you know?

He'd been a little kid — a little kid who watched boxing with his dad; a little kid who loved the movie Rocky. He'd just assumed back then that "in the ring" meant "in a boxing match," and he'd never given it any more thought since.

A giant ring, you know?

Shit. Maybe Procopides was in real danger. Moot got up from his desk and went back to see Capitaine Lavoisier.

The defective cryostat cluster was ten kilometers away; it would take the monorail about ten minutes to bring Theo there. The cab's headlight beams sliced into the darkness. There were fluorescent lighting fixtures throughout the whole tunnel, but it was pointless to illuminate all twenty-seven kilometers of it.

Finally, the monorail arrived at the location of the wonky cryostat cluster. Theo stopped the train, disembarked, found the panel for controlling the local lighting, and turned it on for fifty meters ahead and behind him. He then retrieved his tool kit and headed over to the defective unit.