Logan nodded slowly. “That might work. We could start with the thirties.”

“The thirties?” Ms. Ramanujan repeated.

“The nineteen thirties, yes.”

The woman’s face went strangely blank. She picked up the ID card, which she’d placed on the desk, looked at it, then replaced it on the polished wood. After a moment, she looked up again. “Dr. Logan,” she said, “there are records chronicling over eleven thousand research projects here. The total number of documents attached to those projects approaches two and a half million. Do you expect me to retrieve” — she did a quick calculation — “some two hundred thousand documents for your perusal?”

“No, no,” Logan said quickly.

“Then what do you suggest?”

“If I could just do my own, ah, browsing through the stacks, it would probably give me a better indication of what I’m searching for — and perhaps very quickly, as well.”

There was a pause. “Researchers are not normally admitted to the stacks themselves,” the woman said. “Especially temporary researchers. It is most unusual.”

In response, Logan let Olafson’s letter peep out again from his jacket pocket.

The archivist sighed. “Very well. You may use that table over there, if you need to. But take no more than five folders from the stacks at a time. And please be careful when you refile them.”

“I will,” Logan assured her. “Thank you.”

Over the next three hours, Logan — under the watchful gaze of the archivist — moved back and forth between the stacks and the research table, thick folders in hand each time. He opened the folders and scanned them quickly, scribbling observations into a small notebook with a gold pen. At first, his investigations took him all over the large room. But later, he narrowed his concentration to a much smaller area. Now his examination of the folders became more studious, his reading slower. At last he put the final set of folders away, and — instead of doing additional reading — moved from stack to stack, gazing into various drawers, all the time making notations in his journal as if tallying something. Finally, he put the notebook away and returned to the archivist.

“Thank you,” he said.

Ms. Ramanujan inclined her head as she returned his ID card.

“I have a question. Extensive as these files are, there doesn’t seem to be anything more recent than 2000.”

“That is correct. These archives contain only files of closed or inactive research.”

“Then where is the more recent documentation kept?”

“Some of it, of course, is kept with the scientists doing the research. The rest is in archive two, beyond that door.” And she pointed toward the far end of the room.

“I see. Thank you again.” And Logan turned away, heading in the indicated direction.

“Wait—” the woman began. But Logan was already moving quickly toward the back of the room, his footsteps echoing on the marble floor.

At the back of the vast space — as he’d noticed upon first entering — was a security station, blocking the door beyond. A lone man in the garb of Lux’s security staff sat at a desk within it. He stood up as Logan approached.

“May I help you?” he asked.

“I’d like to examine the recent archives,” Logan said, nodding toward the door.

“Your ID, please,” the guard said.

To save time, Logan presented not only the ID but the letter from Olafson as well.

The guard examined them, then handed them back. “I’m sorry, sir, but you have insufficient privileges to access archive two.”

“But this letter from Dr. Olafson—”

“I’m sorry, sir,” the guard repeated in a firmer tone, “but only persons with a level-A access or greater are permitted past this door.”

Level A? Logan had never heard of such a thing. In fact, during his time at Lux, he hadn’t been aware of any access levels at all. “But—” he began, taking a step forward.

In response, the guard moved to block his progress. As he did so, Logan caught sight of a nightstick and a can of Mace snugged into the man’s heavy service belt.

“I see,” Logan said slowly. Then he nodded, turned, and made his way back through the stacks and into the basement corridor beyond.

It was quarter to seven when Logan knocked on the door of the director’s inner office.

“Come in,” came the disembodied voice from beyond.

When Logan stepped inside, Olafson was standing before a small mirror, adjusting his tie.

“Your secretary’s gone for the day,” Logan said. “Oh, I’m sorry — were you on your way to dinner?”

“It can wait.” Olafson shrugged into his suit jacket, then took a seat behind the desk. “You’ve got something?”

“Something, yes. And I need something — from you.”

Olafson spread out his hands, palm up, as if to say I’m at your disposal.

Logan placed his duffel on the arm of one of the chairs arranged before the desk, then sat down. Opening the duffel, he pulled something out: a badly charred piece of paper inside an envelope. He handed it to Olafson, who scrutinized it carefully.

“I found that among a pile of burned papers in the forgotten room’s fireplace,” he said.

Olafson continued to look at it. “It seems to be three men in lab coats, standing behind a worktable.”

“Not a worktable. The worktable that’s still in the room. You can tell by that deep scar in the wood, near the left corner.”

“Even so, it’s impossible to identify the people. The images have been burned away from the chest up.”

“That’s correct,” Logan replied. “But the photo can tell us something nevertheless.” Reaching into his duffel again, he took out a piece of paper, folded it in half, and held the bottom half up for the director to see. It was a bright, cartoonish picture of an exaggeratedly rotund man standing on the deck of a ship in heavy seas — wearing a blue double-breasted yachtsman’s jacket, white shorts, and a beanie — gazing bemusedly down at an obviously seasick woman lying beneath a blanket on a deck chair.

Olafson squinted at it. “What about it?”

Now Logan unfolded the top half and let Olafson see the paper in its entirety. The logo of a magazine, The New Yorker, was emblazoned across the top of the sheet, along with a date: July 16, 1932.

“The Newport library has an excellent periodical collection,” Logan said. “They wouldn’t let me bring the actual issue, but they did make a color Xerox of the cover for me.”

“I don’t understand,” Olafson said.

“Take a closer look at the burned photograph. Notice those letters and periodicals sitting on the desk? They are all too blurry to make out — except for the magazine cover featuring a porcine man in an odd yachtsman’s uniform. Look closely; you can just make it out. It’s obviously not a cover from a slick such as Colliers, Life, or the Saturday Evening Post. In fact, it looked to me like a quintessential New Yorker cover.” He put the paper back in his duffel. “So now we have a terminus post quem for the work being done in that room. It was in use at least as late as the summer of 1932.”

“I see.”

“And that puts to rest any question about who was using the room. Lux was using that room — in addition to, or instead of, the mansion’s initial owner. And speaking of the owner: I checked the original blueprints for Dark Gables in Strachey’s office. They did not include the forgotten room.” Logan picked up the charred fragment of photograph and returned it to his duffel. “Have you heard of something called Project Sin?”

“Project Sin?” Olafson frowned. “No.”

“Please think carefully. ‘Sin’ may well be just the beginning of a word. No Lux project of that name comes to mind?”

When Olafson shook his head, Logan pulled another glassine envelope — this one containing the bit of burnt memo he had also recovered from the fireplace — and handed it to Olafson.