The steward emerged from the wheelhouse and stood at the rail. “What do you make of her, sir?”

Janvier shrugged. “God knows. Better get the captain.”

A third sailor appeared in the conning tower, a signaling lamp in his hands. The submarine moved in closer, narrowing the gap, and the lamp started to wink rapidly.

A reserve naval officer, Janvier had no difficulty in reading the signal for himself. When he had deciphered it he stood at the rail frowning for a moment, then went into the wheelhouse and unhooked the signal-lamp.

As he moved back to the rail, the light flickered again from the conning tower, repeating her request. As Janvier replied with the “Message received” signal, the captain came up the ladder from the well-deck, the quartermaster close behind.

Henri Duclos was nearly fifty, and after thirty years at sea, five of them as a corvette captain with the Free French Navy, he found it difficult to be surprised by anything.

“What’s all this?” he demanded.

“They’ve made the same signal twice,” Janvier told him.

“ "Heave to. I wish to come aboard." “

“What have you replied?”

“Message received.”

Duclos went into the wheelhouse and came back with a pair of binoculars. He examined the submarine for a moment and grunted. “She’s French all right. I can see the uniforms. Small for a sub, though.” He handed the binoculars to the quartermaster. “What do you make of her?”

The old man took his time and then nodded. “L’Alouette. I saw her in Oran last year when the fleet was exercising. An ex-U-boat. Experimental job the Germans were working on at the end of the war. One of those the navy took over.”

“So now we know who she is,” Duclos said. “The point is what in the hell does she want with us?” He turned to Janvier. “Ask her to be more explicit.”