WIQKO QOPBG JEXLO began the code in front of Beth, five-letter block after five-letter block. She looked at the clock. Three in the morning.

Without any hope at all, she put in PERXCOMANDANTE for the machine’s right-hand wheel and began trying different positions—rodding, Peggy called it, because of the slim cardboard rods with letters printed along them in the order they appeared in the wiring of each Enigma wheel. Peggy had shown Beth how to slide the rods under the encoded text to try to find a point where the text of those all-important common phrases began to appear. Cribs, Beth reminded herself, not phrases. Everything has a special name here. It sounded easy, looking for places where there was no letter overlap, but there were seventy-eight different trials to make in order to cover all twenty-six positions of each of the machine’s three wheels . . .

Her eyes were aching by the time she found something. The first three letters paired up with the rod, P-E-R . . . but it gave the fourth letter as S, not X. She nearly switched over to the next, but paused.

Is there another crib starting PERS?

Beth wavered, then swiped Dilly’s Italian dictionary and flipped to P. Persona . . . personale . . .

“Jean,” she asked the nearest girl, “could personale be a crib?” It was the first time she’d addressed anyone in the Cottage unprompted.

“Maybe?” came the distracted answer. Beth swiveled in her chair, flipping her plait over one shoulder. “Personale,” she muttered. Meaning “Personal for.” Surely the Italian navy had occasion to mark things Personal for ____. It gave her five more letter couplings to check: she had P-E-R-S; now to try for O-N-A-L-E—

Clicks. She’d heard the other girls tossing that word around for weeks, and now she saw why, because things were going click right on the rods in front of her. Direct clicks when both letters of a crib phrase came up side by side on the same rod; Dilly called them beetles for some reason. Then cross-clicks when one crib letter came up on one rod, and the other on a second rod; Dilly called those starfish, and Beth’s breath stopped when she realized she had one. She hadn’t been able to see it before, it hadn’t made sense, but suddenly this bit right in front of her came swimming out of the rows of letters.

Well, if it was “personal for,” then it stood to reason that next there would be a name, a rank, an honorific . . . She pulled out two letters, N-O. Beth dropped her rods and went pawing through the cribs again. Signor? Painstakingly she pulled S-I-G-out of the mess, then the R, then gobbledygook that was probably a man’s name. But she had enough, she could go after some of the missing rod couplings now . . . Her braid fell over her shoulder again, getting in the way, and she twisted it up behind her neck and pushed a pencil through it. Another click . . .

“Beth,” one of the other girls said. “Go home, your shift’s over.” Beth didn’t hear. Her nose was almost touching the paper in front of her, the letters marching along in a straight line over her rods, but somewhere behind her eyes she could see them spiraling like rose petals, unspooling, floating from nonsense into order. She was working fast now, sliding the rods with her left hand, elbow holding the Italian dictionary open. She lost an hour on a crib that didn’t work, then tried another and that was better, the clicks started coming right away . . .

Dilly Knox came in, already looking exhausted. “Anyone seen my ’baccy?” The new shift of girls went on the usual hunt for his tobacco tin. “What are you still doing here, Miss—what’s your name again? I thought you were on the night shift.”

Beth just handed him her worked-out message and waited, pulse racing. She’d never felt like this in her life, very light and remote, not entirely back in the present. She’d been going at it six straight hours. The message was a mess of scribbles, still gobbledygook in patches, but she’d broken it open into lines of Italian.

Her boss’s smile made her heart turn over. “Oh, well done!” he all but caroled. “Well done, you! Bess?”

“Beth,” she said, feeling a smile break over her face. “What—what does it say?”

He passed it off to one of the other girls, who spoke Italian. “Probably a routine weather report or something.”

“Oh.” Her cautious, dawning pleasure sank.

“It doesn’t matter what it says, dear girl. Just that you broke it. We’ve had such trouble cracking Italian Enigma since they entered the war. This might be the best break we’ve had in ages.”

“. . . It is?” Beth looked around at the others, wondering if they’d think she was showing off. But they were grinning; Peggy clapped. “It was an accident—”

“Makes no difference. That’s how it happens. Now we have this, we’ll get the rest quicker. Until the Eyeties change things up, at any rate.” He gave her a swift assessing look. “You need breakfast, a proper one. Come with me.”

DILLY DROVE HIS Baby Austin out through the gates of Bletchley Park like the Four Horsemen of the Apocalypse were after them and was soon tearing up Watling Street with absolutely no regard for either tank traps or passing traffic. At any other time, Beth would have been sure she was about to die in a ditch, but rather than clutching the door and whimpering, she sat statue-passive in the passenger seat. She was still coming down from another world, electric and distant, spirals of letters turning lazily behind her eyelids.

Dilly didn’t seem to expect conversation. Hands only now and then connecting with the wheel, he careened them down Clappins Lane and then a long woodland drive, pulling up at last before a gracious, gabled manor house. “Courns Wood,” he announced, swinging out of the car. “I call it home, though with the war on, I’m hardly here. Olive!” he called, moving into a dim paneled hall. A plump graying woman appeared, dusting flour off her hands. “My wife,” Dilly said, somewhat unnecessarily. “Olive, meet Beth—a budding cryptanalyst in need of sustenance.”

“Hello, dear,” Mrs. Knox greeted Beth tranquilly, as if utterly unsurprised to find a disheveled young woman trailing behind her husband after what had very clearly been a long night. If you were married to Dilly Knox, perhaps you got used to living in a perpetual Wonderland. “Could you eat an omelet?” she said, then answered her own question, clearly seeing Beth was beyond speech. “I’ll bring two. Library, dears . . .”

Somehow Beth found herself in a disorganized study lined with books and warmed by a roaring wood fire, gin and tonic in her hand. “Drink up,” Dilly said, mixing one for himself and settling into a leather chair opposite. “Nothing like a stiff gin after a hard night with the rods and cribs.”

Beth didn’t stop and think, What would Mother say? She just lifted her glass and drank half. The gin fizzed like sunshine and lemons.

“Cheers.” Her boss raised his own glass, eyes sparkling. “I think you’ll be a good addition to the Cottage, m’dear.”

“I thought I was going to be sacked.”

“Nonsense.” He chuckled. “Now, what did you do before coming to BP?”

Nothing. “I was just—the daughter at home.”

“University?” Beth shook her head. “Pity. What are your plans?”

“What plans?”

“After the war, of course!”

There were tank traps the length of Watling Street, and every headline was full of German Messerschmitts poking their snouts over the coast. “Are the Germans going to give us an after the war?” Beth heard herself wonder.

It was the kind of thing no one said aloud, but Dilly didn’t chide her for letting down morale. “There’s always an after. Just depends what it looks like. Finish that drink; you’ll feel worlds better.”

Beth lifted the glass again, then stopped. She realized in a sudden rush of returning caution how this looked: a girl of twenty-four drinking gin at ten in the morning with a man in his fifties, alone in his private library. What other people might think.

He seemed to know what was flashing through her mind. “You know why I only want gels for my team?” he asked, eyes no longer vague behind the glasses. “Not because I want pretty faces around me, though heaven knows you’re all nicer to look at than a lot of university swots with horse teeth and dandruff. No, I take gels as my new recruits because they are far better, in my experience, at this kind of work.”

Beth blinked. No one had ever told her young ladies were better at any kind of work than men, unless it was cooking or sewing.

“These young mathematicians and chess players in the other huts—they do similar work to what we do, rodding and cribs, but men bring egos into it. They compete, they show off, they don’t even try to do it my way before they’re telling me how to do it better. We don’t have time for that, there’s a war on. And I’ve been doing this work since the last one—I helped crack the Zimmermann telegram, for God’s sake.”