“So, your shipboard friend—” A nudge. “Fiancé?”

“Oh, just a boyfriend,” Osla murmured, banging away at the punching machine. She’d had boyfriends since she was sixteen, casual crushes conducted over late-night dancing and the occasional kiss in the back of a taxi. Nothing serious. Philip had gone to sea in February; they’d barely known each other six weeks—dancing at the Café de Paris when Osla got a night off from the Hurricane factory; long evenings when he’d drive to her shared digs and lie with his head in her lap as they listened to gramophone records and chatted the night away. “Are you falling for your handsome prince?” Sally Norton teased one evening after Philip ambled out after midnight.

“He’s not my prince,” Osla retorted. “He’s looking for a girl to splash out with before going to war, that’s all. For me, he’s just another boyfriend.”

Except Philip was the only one who made her bones burn. The first kisses of her life that felt dangerous. The last night before he’d shipped out, he’d gripped her hand tighter than usual and said abruptly, “Write to me, Os? If you do, I’ll write to you. I haven’t anyone to write to, really.”

“I’ll write,” Osla had said, no jokes, no teasing.

He leaned in for another of those long, heated doorstep kisses, the ones that went on and on, his hands moving across her back, her fingers deep in his hair. Before he pulled away, he pressed something into her hand and then leaned down and crushed his lips to her folded fingers for a long moment. “So long, princess.”

She’d opened her hand and seen the cool glitter of his naval insignia like a little jeweled pin. As she fastened it to her lapel like a brooch, she warned herself again, Careful. Her mother spent all her time making a mug of herself over unsuitable men, and Osla was determined to be the apple who fell a long way from that tree.

Someone came over, a scholarly type in an unraveling jumper, interrupting Osla’s musings. “Give me a hand, girls? I need this report . . .” And he rattled off a series of numbers.

“Make him out a copy, dear,” Miss Senyard directed, pulling the report, and Osla obeyed as the man nearly danced on his toes with impatience. Osla remembered red-haired Giles saying the Park was stuffed with Oxford dons and Cambridge chess champions, and wondered where he worked—if he was one of the brainy ones working the middle stage of this process: taking the raw gibberish from German radio traffic, the stuff they were registering and logging, and breaking it apart until it was something that could be read, translated, analyzed, and filed in sections like this one.

“Thanks.” The man flew off with his copied report, leaving Osla feeling both pleased and deflated, and she went back to binding and filing signals. She had absolutely no idea what had just happened, why that one report had been needed, and she never would know. That was all right; it was important to someone, and she’d played her part . . . but there wasn’t any doubt this job was a lot simpler than she’d hoped for. The pace might have been frenetic, but anyone with a teaspoon of brains and a little attention to detail could bind and file.

Dear Philip: Am I an ungrateful cow if I’ve gone from wishing I could do more for the war than bang sheets of Dural, to wishing I could do more for the war than wield a punching machine?

“My job’s a yawn, so let’s hear about yours,” Osla told her billet-mate that night. Mab had just slipped in from the outdoor loo, and Osla lay across her narrow bed in slip and knickers, trying to get in a chapter of Vanity Fair before lights-out. “Day one—how was it?”

“Not bad.” Mab stripped out of the robe she’d donned to go downstairs, standing in her own slip and knickers. “Can’t say much more than that, can I? All this secrecy; are we even allowed to ask each other ‘How’s work?’” Mab’s slip was nylon and very worn. Osla, in peach silk with French lace inserts, remembered the girls of her deb season tittering about the poor girls, by which they meant the ones who wore the same frock twice in one week . . . she’d watched Mab unpack exactly four dresses from her suitcase into their shared wardrobe, all perfectly pressed, and felt self-conscious unpacking more than four of her own.

“Mind you,” Mab went on, picking up her hairbrush, “I don’t think our nosy landlady cares about secrecy. Did you see her pursing her lips over supper when we wouldn’t answer every question?”

“And good luck to anyone else trying to get a word in.” Osla had tried to ask the washed-out daughter a thing or two, but the poor mouse hadn’t uttered a peep around her mother’s peppering questions. Osla still wasn’t sure if the girl’s name was Beth or Bess. She wondered if she could get by with darling through the entire war.

“I’ll tell you one thing about my hut.” Mab’s hair crackled as she stroked the brush vigorously through it. “It’s got my future husband in it somewhere. I’ve never seen so many eligible bachelors in my life.”

“Oooh. Glamour boys?”

“I said eligible, not glamorous.” Mab gave that grin of hers, the one that cracked the cool, guarded expression on her rather severe face and made her look like a pirate who had spotted a Spanish treasure galleon on the horizon. HMS Queen Mab, out to chase and board the unsuspecting bachelors of Bletchley Park, thought Osla. “Anyone in your hut catch your eye?”

“Oh, I’m not looking for a fellow,” Osla said airily.

Dear Philip: It’s a madhouse, and maybe my job’s a touch undemanding . . . but I think I like it here.

Chapter 7

June 1940

If Bletchley Park had a motto, Mab thought, it would be You dinnae need to know.

“Are the other huts set up like this one?” Mab asked as she was whisked through the central corridor of Hut 6.

“You dinnae need to know,” said her new supervisor, a middle-aged woman with a crisp Scottish voice. “You’re assigned to the Decoding Room . . .” And she ushered Mab into a box of a place, all lino and blackout curtains, filing cabinets and wooden trestle tables. But it was the two machines that made Mab stare: awkward composite things bristling with three rows of keys, a set of wheels on one side, big spools of tape somehow attached. Mab thought they looked like a cross between a typewriter, a shop till, and a telephone switchboard. A woman sat hammering at one of the machines, hunched like Quasimodo (The Hunchback of Notre Dame had been number 34 on “100 Classic Literary Works for the Well-Read Lady”).

“Miss Churt, is it?” The Scotswoman led Mab to the unoccupied machine. “Most of our girls are Newnham College or Girton College; where did you graduate?”

“Claybourn secretarial course, top of my class.” Take that, Girton College. Mab wasn’t going to be embarrassed by her lack of schooling any more than she was going to be embarrassed by her nylon underwear in the face of Osla’s French lace slips.

“I suppose it disnae matter,” the Scotswoman said dubiously. “This is your Typex machine. It’s mocked up to decipher the encrypted messages the Germans send by radio to their officers in the field. Each service of the German armed forces sends those messages using a service-specific key, over their own wireless networks, and the settings of that key are changed daily. Our listening stations across Britain and abroad intercept these messages, transcribe them, and send them to BP. By the time they make their way to the Decoding Room, they are given to you as coded messages.” She held up one finger. “You will be given settings, a different setting for each key”—a second finger—“you will align your machine to those settings”—a third finger—“and you will punch the coded messages into the machine so they can be decoded into German. Do you understand?”

Not really. “Yes, of course.”

“You’ll get an hour at noon for dinner, and there is a toilet block outside. This hut works round the clock, Miss Churt. Fourteen days on the nine-to-four, then fourteen days on the four-to-midnight, then twelve days on the midnight-to-nine.”

The Scotswoman bustled off to some other compartment of Hut 6. The girl at the other Typex machine, snail-hunched in a pebbly jumper, slid a stack of papers over as Mab took her seat. “That’s the rest of the day’s Red,” she said without preamble. “Bit late today. The boys in Hut 3 get tetchy if we haven’t got it for them by breakfast. Here’s the setting.” She showed Mab how to fix up her Typex machine for decoding Red traffic: the order for the three wheels; then something she called the Ringstellung, rattling off numbers that each equated to a letter of the alphabet . . . Mab followed along, head swimming. “Then a check to be sure the setup’s correct; set each of your three wheels to A and type out a keyboard alphabet. If it corresponds exactly letter for letter, you’re ready to start. See?”