"Yes, a handsome specimen," von Till said jovially. "I'm honored you could identify it. Sunk by an American destroyer off Iwo Jima in 1945, raised by Minerva Lines in 1951. I've found the combination of submarine and aircraft a most useful method of delivering small cargoes into areas that demand extreme discretion."

"A handy toy for also attacking United States airfields and research ships," Pitt added.

"Touché, Major," von Till murmured. "At dinner the other night you guessed that the plane came from the sea. You were groping blindly, but you came much closer than you thought."

"I can see that now." Pitt shot a quick glance at the tunnel entrance. Two more guards leaned negligently against the walls of the opening, their machine pistols hung carelessly over their shoulders. Pitt started to say: "The antique Albatros—"

"Correction," von Till interrupted. "A replica of an Albatros. For my purposes a slow, bi-wing aircraft was the most efficient means of landing and taking off on short fields, dark beaches or in water beside a ship; the lower wing can, or should I say could, fold downward in the shape of hydrofoil pontoons. I used the Albatros D-3 design with a more modern engine, of course, because the aerodynamics provided the perfect answer to my requirements. And an old shabby looking airplane would never be suspected of, shall we say, slightly illegal activities. A pity it will never fly again."

Von Till pulled a box of cigarettes from his breast pocket and lit one. Then he went on.

"My delivery plane was never meant to be armed or flown in combat. It was only after I had no alternative but to assault Brady Field and your precious research ship that I had the guns installed; a drastic move perhaps but your Commander Gunn refused to be discouraged by my subtle efforts to sabotage his expedition. There was little to fear from a Sunday swimmer or a diving tourist discovering my little underwater modus operandi. However, a trained ocean scientist, that was something else again. I could not take the risk. The raid was, I am still convinced, an excellent plan. Colonel Lewis would have had no choice but to order the…its name escapes me, ah yes, the First Attempt to evacuate the Thasos coast if the attack had continued unhindered. You couldn't have known, of course, that the Albatros intended to make a token strafing run against the ship immediately after it neutralized the airfield. Inopportunely, Major Pitt, you blundered onto the scene and ruined everything."

"The fortunes of war," Pitt offered sarcastically.

"It is a shame Willie cannot be here to hear you say that."

"Where is good old Peeping-Tom Willie?" Pitt asked.