“You’re both wrong,” a third, balding man said, coming over. “It’s Norway.”

Which meant Fortitude North in Scotland was doing its job.

“Can’t you at least give us a hint?” the horsy woman said. “You can’t know how difficult it is to make plans, not knowing what’s going to happen.”

“Everyone knows it’s Normandy,” Wembley said. “In the first place, the Pas de Calais is where Hitler will be expecting it.”

“That’s because it’s the only logical point of attack,” the other man said, his face getting red. “It’s the shortest distance across the Channel, and the shortest land route to the Ruhr is from there. It has the best ports—”

“Which is why we’re going to invade at Normandy,” Wembley said loudly. “Hitler will be concentrating his troops at Calais. He won’t be expecting the attack to come at Normandy. And Normandy—”

Ernest had to stop this. It was all much too close to the truth. “You both make interesting cases,” he said, and turned to Mrs. Wembley. “Have you read Agatha Christie’s latest mystery novel?”

“Hmmph,” Wembley said, drawing himself up.

Ernest ignored him. “Have you?”

“Why, yes,” she said. “Are you saying her book—”

He leaned toward her confidentially. “I can’t say anything about the invasion—it’s all top secret, you know—but if I were in charge of it,” he lowered his voice, “I’d take all of Agatha Christie’s novels off the shelves till fall.”

“You would?” she said breathlessly.

“Or I’d have their titles painted over, like you English did with your train stations,” he whispered, emphasizing the word train.

“Now if you’ll excuse me, ladies,” he said, then bowed slightly and limped back over to Cess and Chasuble, who were plotting how to get their hands on the real liquor.

“I fail to see what detective novels have to do with the invasion,” he heard Wembley grumble as he walked away.

“It’s a riddle, darling,” his wife said. “The answer’s in the title of one of her books.”

“Oh, I do love puzzles,” the horsy woman said.

“He mentioned railway stations,” Mrs. Wembley said musingly. “Let’s see, there’s The Mystery of the Blue Train. And The A.B.C. Murders. A.B.C. Could that be some sort of code, do you think?”

Cess looked over at the group. “What did you say to them?” he asked curiously.

Ernest told them. “I got the idea from those mysteries Gwendolyn’s always reading. Moncrieff told us ‘subtle,’ ” he said, picking up an impaled pilchard-on-a-toothpick and eyeing it dubiously. “But I think it may have been a bit too subtle.” He put the pilchard back on the tray and rejoined the group.

“It could be something with a place-name in it,” Mrs. Wembley was saying. “There’s Murder in Mesopotamia—”

“As much as the Allies cherish the value of a surprise,” the balding man said, “I doubt very much they will invade by way of Baghdad.”

“Oh, of course,” she said, flustered. “How silly of me. Oh, I can’t think. What else did she write? There’s Murder at the Vicarage, but that can’t be it, and the one where he did it, and the one where the two of them—”