What Alistair had not figured out was a way for the head to communicate with the wings. As another safeguard to protect Bridgette’s identity and theirs, the others were to have no overt contact with her. If her cover was blown, without radio connection to Bern, the whole operation would naturally fall apart. It was critical that Labrador’s identity, address, and workplace be kept secret. But various situations were bound to jump up that would require her to contact her teammates individually.

This dilemma was unique to his professional experience, and Alistair had racked his brain trying to come up with a way out of it, but nothing had clicked, and he was running out of time. As the date neared to release them to their fates, he decided to lay the problem before the sharp minds of his young charges.

Brad—Limpet—suggested a central location to leave coded chalk marks. Cutting on wood would require too much time and attract attention, and the French were banned from carrying knives. Alistair immediately rejected the proposal as too obvious. A collection of chalk marks on a wall, doorstep, tree, or telephone pole was a dead giveaway to Nazi patrols and the collaborationist French police, and they’d lie in wait for the next operative to show himself. There was also the new danger of arrest by the Gestapo if a Parisian was found with any sort of marking medium other than pencils and fountain pens in pockets or purses, especially chalk. The discovery automatically stamped the owner as a member of the Resistance.

It was Bridgette who suggested a mural as the solution.

At this point, the group was aware that they would be living in the Latin Quarter of Paris, though Alistair had informed each of them of their accommodations privately with the stern admonition that they were to keep their addresses secret from the others. He had little expectation of his orders holding, however. The group members could bump into one another at the mail chute, or discover the locations of one another’s abodes by the simple act of catching their teammates entering and leaving their residences.

“Explain, Labrador,” he said.

“How can the Germans object to decorating a drab wall with a beautiful piece of art during wartime?” Bridgette replied. “If you can arrange it with the convent, Major, I propose that I paint a mural on the outside of their courtyard wall as a means to communicate in code.”

They had been shown a picture of the house with its attached courtyard wall and convent behind. “You mean use a wall painting as a code pad?” Alistair said. Yes! he thought jubilantly and said, “It can be arranged.”