“Yes, sir?”

“In my office. I’ve got one for you.”

She exhaled with relief. She belonged in the field. Even when the field was cold and miserable and she needed a better coat, she’d rather wander the streets of Chicago in the snow than sit there and type beside the furnace.

She left the warm spot with only a little rue. Her employer held the frosted glass door open as she passed him and took the seat across from his enormous oak desk. A simple name plaque announced that he was the owner of this desk, and the finely stenciled name and all-seeing eye logo on the door’s glass announced he was the owner of this office, and that he never slept. Everything here belonged to him, and he liked to make sure everyone knew it.

“All right, Mr. Pinkerton. Brief me.”

“Listen to you there, picking up the lingo like you’re one of the boys. Never thought I’d see the day,” he said, as he parked himself behind the desk, facing her. The wheels on his chair bottom rolled back and forth as he fidgeted. He put his elbows atop a pile of ledgers, reached for a cigar, and lit it. Then he used his knuckles to drag a big glass ashtray within easier reach.

“Rose uses the lingo, too.”

“Rose is a special case.”

“And I’m not?”

The old man grinned. His white-bearded cheeks inflated and puffed as he sucked the cigar to life. “All my employees are special. Is that what you want to hear?”

“Not really.”

“Good, because it isn’t true. How was that art job in Philly? You turned that one over pretty quick.”

“It was easy,” she said, which meant it hadn’t been very interesting. “Sometimes the most obvious answer is the right one. Alastair Duggard’s wife destroyed the painting.”

“Why?”

“Because her husband liked it. And because she found out about his mistress, who she didn’t like at all.”

“Most obvious answer, indeed,” he said, tapping a scrap of ash into the tray. “Too bad we couldn’t get it back for him, but I suppose it’s his own fault it’s gone. He paid up?”

“He paid up. I was recording the last of the invoices when—”

“In Kelly’s chair, I saw.”

“I was cold. I am cold. It’s cold.”

“You’re in Chicago, dear.” He said it “Shi-kah-go” like the locals, despite his native (if fading) Glaswegian patter. “It’s cold here more often than not. You need warmer clothes, or thicker blood. Living down there in the jungles … it’ll make you soft.”

She didn’t bother to correct him anymore when he talked about Virginia’s jungles. He’d never seen Virginia—or a jungle, for that matter—but she had better things to do than waste her breath convincing him of it. “I need to move around more, that’s all. And I believe you can help me with that—you said you’ve got a case for me?”

“I do indeed. And it’s a big one, too.” He hesitated, leaving something unsaid.

“Sir?”

“I’m not going to lie to you, Maria: I can’t tell if you’re the best candidate for this one, or the worst possible choice.”

“Another job working for the Union, I take it? I managed the last assignment to everyone’s satisfaction.”

“That you did, but this one is … closer to the heart.”

She was confused. “My heart? Your heart?”

“To President Lincoln’s heart. Literally and figuratively.”

“You … you want me to work for Abraham Lincoln?”

“The situation is unusual—but not the same kind of unusual as usual.”

“You’ve always had a way with words, sir.”

He looked past her shoulder. “Do me a favor, dear—reach behind you and shut that door.”

She did as he asked, and he continued, but in a quieter, more serious tone. “Mr. Lincoln and I have remained friends for many years, despite the incident at the Ford. Depending on who you ask, my son either saved his life or ruined it, and Mrs. Lincoln held the whole thing against us for a while. Abe’s recovery came so slowly, and so incompletely.… Still, the president has continued to accept our service in good faith. He presently employs one of our D.C. operatives—a young man named Nelson Wellers, who happens to be a physician.”

“These days, I guess Mr. Lincoln needs a doctor more than a bodyguard.” Maria cocked her head and frowned. “But this Dr. Wellers is no longer sufficient? I worked as a nurse, but quite briefly, I want you to know; I wasn’t cut out for it. If you’re only looking to send me because I’m a woman—”

“No, no, no.” He dismissed her concerns with a wave of his cigar, leaving a trail of smoke to underline his impatience. “Wellers is fine. Nothing wrong with him. Mr. Lincoln doesn’t need a nursemaid or another security agent for himself. He wants to hire someone to investigate a crime against somebody else.”

“Oh.”

“Really, Maria. If I wanted to insult you, I’d do it more directly.” He lifted one elbow and retrieved a file, then set his cigar in the glass tray’s groove. “So here are the brass tacks. The man in question is Gideon Armistead Bardsley, a doctor from Alabama. Not the kind of doctor who fixes you—this one’s an inventor. A scientist.”

“Another negro,” she noted from the picture, a good daguerreotype that showed a long-waisted, broad-shouldered man in a suit that fit him well. He must be a little younger than she was, but she detected some lightness at his temples, the premature gray of someone who works too hard. “I’m sensing a theme.”

“Twice isn’t a theme, it’s a coincidence. Will it be a problem?”

“Wasn’t a problem last time. Won’t be a problem this time.”

“Good.” He slid some paperwork across the desk. As Maria started to read, he pitched her the highlights. “Dr. Bardsley was a slave in Alabama until a dozen years ago, when he escaped. He got as far as Tennessee.”

“No one sent him back?” The Bloodhound Laws were still on the books in the South, and anyone who’d returned the runaway would’ve been richly compensated.

“The University of Tennessee at Fort Chattanooga paid for his freedom, on the condition that he stayed there and made them look good. Brilliant man, this Bardsley fellow. A real-life genius, if his diplomas can be believed. In four years he earned a master’s degree in some kind of advanced math, and a doctorate in electromechanical engineering—a brand-new field. I don’t think any other school in the South even offers such a degree. The next year, he bought freedom for the rest of his family still living: a couple of brothers, his mother, and a nephew.”

“What was he working on in Chattanooga?” she asked, still absorbing the information on the pages before her. “It must’ve been profitable. That kind of buyout takes more than chump change.”

“Civic planning, if the public information can be believed. He felt there was no good reason you couldn’t generate power for entire cities with old-fashioned technology like water. He was developing schematics for water turbines that could convert the flow of rivers into electricity with the right kind of dams and wires. It’s a bit over my head, to be honest, even if it is true.”

“You think it’s not?”

“I think he was working on military projects. I can’t imagine any other reason the school would’ve paid for his life and his education.”

“A negro designing weapons for use against the North? I don’t know about that.”

“Maybe not weapons. Armies and navies need a million and one things to operate smoothly. He could’ve been working on any of ’em. When you meet him, you can ask him.”

“Is he still in Washington?” The document in her hand was a courthouse copy, identifying him as a free man of color with an address in the capital.

“In 1876 he defected to the Union, taking his mother and nephew with him. He started out in Philadelphia, but moved to D.C. when Mr. Lincoln took a personal interest in one of his projects.”

Maria flipped through another page or two of biography. She stopped at an engraving of a machine emblazoned across a patent application. “‘The Bardsley Automatic Computational and Calculational Device,’” she read, eyeballing the diagram and marveling at its implied dimensions. “Good heavens, it must be enormous.”

“A whole roomful of a machine, I’m led to understand.”

“A whole mouthful, too. Why do inventors do that? Name their inventions such ridiculous things?”

“Any number of reasons, I’m sure, but the Lincolns agree with you, at least. When Mrs. Lincoln explained the project to Dr. Wellers, she called it a giant mechanical brain—a brain that could think faster, better, and more accurately than any man ever could. Wellers said that such a thing could really fiddle with a fellow’s head, and she laughed … so now the thing is called Fiddlehead for short. Think of it as a code name, if you like that better.”

“Got it. So the Lincolns are … what? Dr. Bardsley’s patrons? Sponsors?”

“Yes. And at the moment, they’re his lifeline.” He passed her a newspaper article, then continued. “Three nights ago, armed men broke into the doctor’s laboratory at the Jefferson Science Center, destroying a great deal of expensive equipment, and doing their best to kill Bardsley in the process.”

She didn’t lift her gaze. “Was the Fiddlehead itself destroyed in the incident?”

“Damaged, yes. Destroyed, no. Apparently the doctor tricked the intruders into vandalizing less interesting equipment.”

She set the newsprint article aside. “So he’s not just a brilliant man, but a clever one, too. Tell me, then: What was this Fiddlehead designed to do? A giant brain, you said, but everyone everywhere has a brain. What makes this one so special? What was it told to think about?”