Well, Mab would take the train back to London the first day she had off. Whatever this post was, there had to be days off, even in wartime. And maybe her living situation in—what was this town called again?—would be decent enough she could see about moving her family here to the country. Better the middle of nowhere among green fields than soon-to-be-bombed London . . . Mab shuddered and went back to Vanity Fair, where Becky Sharp was headed for a new job in the country too, not appearing to worry much about her homeland’s being invaded. But in Becky’s day it had been Napoléon, and Napoléon didn’t have bloody Messerschmitts, did he?

“What’s your name, lovely?” The fondler had switched his attentions to the little brunette in the fur-trimmed coat, who was now the only other passenger in the compartment. His hand began to work away in his pocket. “Just one smile, gorgeous—”

The brunette looked up from her own book, flushing pink, and Mab wondered if she’d have to intervene. Normally she abided by a Londoner’s strict rule of keep your nose out of other folks’ business, but the brunette looked like an absolute lamb in the woods. Just the sort of female Mab both slightly resented and also envied—expensively dressed, pampered skin that a gushy novel would describe as alabaster, the sort of pocket-sized figure all women wanted and all men wanted to take a bite out of. The kind of silly overbred debutante, in short, who had grown up riding ponies and wouldn’t have to lift a finger to bag herself a husband of means and education, but was otherwise completely useless. Any Shoreditch girl could handle a train compartment lothario, but this little bit of crumpet was going to get munched right up.

Mab laid down Vanity Fair with a thump, irritated with the fondler and rather irritated with the brunette too for needing rescuing. But before she could even snap Look here, you . . . the brunette spoke up.

“My goodness, look at the tent in your trousers. I can’t say I’ve ever seen anything quite so obvious. Most fellows do something incredibly creative with their hats at this stage.”

The man’s hand froze. The brunette put her head to one side, eyes widening innocently. “Is something wrong? You aren’t in pain, are you? Chaps always act like they’re in such pain at this point, I’m nobbled if I know why . . .”

The fondler, Mab observed, was red as a beet and had withdrawn his hand from his pocket.

“. . . Really, do you need a doctor? You’re looking absolutely in the basket—”

The man fled the compartment with a mutter. “Feel better soon!” the little brunette called after him, then looked over at Mab, eyes sparkling. “That fixed him.” She flung one silk-stockinged leg over the other with evident satisfaction.

“Nice work,” Mab couldn’t help but say. Not such an easily munched bit of crumpet after all, even if the girl didn’t look a day over eighteen. “If I have to get rid of a fellow like that, I rely on a good icy stare or a kick in the shins.”

“I can’t do an icy stare to save my life. This face simply won’t glower. If I try, fellows tell me I look adorable, and there’s nothing to make you flip your wicket like being told you’re adorable when you’re furious. Now, you’re clearly tall, and you’ve got eyebrows like an empress, so I’m sure you have a very impressive glare?” Tilting her head in invitation.

Mab had been about to retreat into her book, but she couldn’t resist. Arching one brow, she looked down her nose and let her lip curl.

“Now that’s a slap-up stare to freeze the marrow!” The brunette put out a hand. “Osla Kendall.”

Mab shook it, surprised to feel calluses. “Mab Churt.”

“Mab, that’s topping,” Osla approved. “I was going to guess Boadicea or Scarlett O’Hara; someone who could drive a chariot with knives or shoot Yankees on staircases. I got stuck with Osla because my mother went to Oslo and said it was too too utterly divine. What she meant was that I was conceived there. So now I’m named after a city that is being crawled over by Germans, and I’m trying not to take it as a prediction.”

“Could be worse. What if you’d been conceived in Birmingham?” Mab was still trying to make sense of the girl’s work-roughened hands in contrast to her Mayfair drawl. “Surely those calluses didn’t come from finishing school.”

“From building Hurricanes at the Hawker Siddeley factory in Colnbrook.” Osla saluted. “Who knows what I’ll be doing now. I was called to interview in London, and then the strangest summons arrived telling me to go to Bletchley station—”

“But that’s where I’m going.” Startled, Mab dug out the letter in her handbag, much puzzled over when it had arrived in Shoreditch. Turning, she saw an identical letter in Osla’s hand. They held the sheets side by side. Osla’s letter read:

Please report to Station X at Bletchley station, Buckinghamshire, in seven days’ time.

Your postal address is Box 111, c/o the Foreign Office. That is all you need to know.

Commander Denniston

Mab’s was more official—I am desired by the Chief Clerk to inform you that you have been selected for the appointment of Temporary Clerk . . . you should attend for duty in four days’ time, traveling by the 10:40 a.m. train from London (Euston) to the third stop (Bletchley)—but the destination was clearly the same.

“Curiouser and curiouser.” Osla looked thoughtful. “Well, I’m dished—never so much as heard of Bletchley or Station X.”

“Me either,” said Mab, and wished she’d said “Nor I.” Osla’s polished voice and breezy slang were making her self-conscious. “I had an interview in London, too—they asked me about my typing and shorthand. They must’ve got my name from the secretarial course I took last year.”

“They didn’t ask me about typing at all. This hatchet of a woman tested my German and my French, then told me to run along home. About two weeks later, this.” Osla tapped the letter. “What can they want us for?”

Mab shrugged. “I’ll put my hours in for the war doing whatever they want. What matters to me is earning a wage to send home, and being close enough to London to visit every day off.”

“Don’t be so prosy! We could be walking right into our own Agatha Christie novel here, The Mystery of Station X . . .”

Mab adored Agatha Christie. “Murder at Station X: A Hercule Poirot Mystery . . .”

“I prefer Miss Marple,” Osla said decidedly. “She’s exactly like every spinster governess I ever had. Just with arsenic instead of chalk.”

“I like Poirot.” Mab crossed her legs, aware that her shoes, no matter how carefully she’d shined them, looked cheap next to Osla’s hand-stitched pumps. At least my legs are just as good as hers, Mab couldn’t help thinking. Better. That felt rather petty and mean-spirited, but Osla Kendall was so clearly a girl who had everything . . . “Hercule Poirot would give a girl like me a fair hearing,” she went on. “The Miss Marples of the world take one look and decide I’m a tart.”

When the train drew to the third stop at last, Osla whooped “Tallyho!” but Mab’s hopes soon waned.

Half a mile of suitcase dragging from the dreary, crowded station led them to an eight-foot chained fence topped by rolls of barbed wire. The gates were manned by two bored-looking guardsmen. “Can’t come in here,” one said as Mab rummaged for her papers. “Got no pass.”

Mab brushed her hair out of her face. This morning she’d set it into perfect waves with kirby grips, and now she was sweaty and annoyed and her waves were falling out. “Look here, we don’t know what we’re supposed to—”

“Come to the right place, then,” said the guard in a country accent she could barely understand. “Most of ’em here look as if they didn’t know where they was, and God knows what they’m doing.”

Mab gave him the icy stare, but Osla stepped forward, all wide eyes and trembling lips, and the older guard took pity. “I’ll escort you up to the main house. If you want to know where you are,” he added, “you’re at Bletchley Park.”

“What is that?” Mab demanded.

The younger guard sniggered. “It’s the biggest bloody lunatic asylum in Britain.”

THE MANSION LOOKED out over a rolling green expanse of lawn and a small lake—redbrick Victorian with a green copper dome, stuck all over with windows and gables like a Christmas pudding studded with glacé cherries. “Lavatory Gothic,” Osla shuddered, but Mab stared enchanted, unable to keep herself from wandering off the path toward the lake. A proper country house and grounds like Thornfield Hall or Manderley, the kind of house that eligible bachelors were always renting in novels. But even here, war had placed its ugly mass-produced boot firmly on both mansion and personnel. Hideous prefabricated huts dotted the grounds, and people rushed haphazardly across the paths—fewer men in uniform than Mab was used to seeing in London, and certainly more women than she was expecting. They hurried between the huts and mansion in tweeds, knits, and abstracted expressions.

“They all look like they strayed into a labyrinth with no exit,” Osla observed, following Mab toward the lake as the guard stood looking impatient on the path.

“Exactly. Where do you think we—”

They both halted. Crawling out of the lake, soaking wet, plastered with reeds, and clutching a tea mug, was a naked man.