Nothing could be seen in there. And the detector, swing it as they would, picked up no more of the odd droning or bizarre whistling.
Benson settled to three thousand feet, under the cloud bank. His pale and icy eyes had the glitter in them that came from sudden, valuable knowledge — and which meant disaster for someone in the very near future.
“We’re in familiar territory,” said Mac.
Ahead a few miles was an oblong small dot on the scalloped edge of the lake. But its tininess was obviously the result of distance. A glance told that in reality it was immense.
“The abandoned ferry,” nodded Benson. He had known precisely where they were before the sight of the barge told them. “Keep the detector turned back toward the cloud bank. Hear anything? No?”
The Scot kept shaking his head.
Benson sent the plane in a long slant toward the ferry. It was almost night, and the great scow showed only an oblong blackness on the vague white of the beach.
Even Benson could not know that the blackness had been much relieved, from the lake side at least, a moment before.
In the ferry, Smitty was sitting with his big broad back against the side of the hull. A little in front of him, placed so that he could get all too plain a view of what went on, Nellie writhed in the grasp of two men. Her slim, round arms were reddened and bruised. There was a blue patch on her cheek from the blow that had knocked her out.
She was watching the man with the battered felt hat. Smitty was watching that man, too, and straining at his bonds in a way that made the others highly uneasy, in spite of the size and strength of the rope.
The man with the battered hat was smoking a cigar, and puffing the end hard till a glowing red cone could be built up.
“You’ll answer,” he said coldly to the girl. “Or that big clown over there will answer for you. And you know what we want to hear, too. What does this guy Benson know about us, so far? And what is his next move?”
Nellie straightened to all her five feet, and she laughed in the man’s face.
“Why you little hellcat—”
The man with the cigar stepped savagely toward her.
Then a loud buzzing filled the hull of the ferry.
“The siren,” one of the men said. “They’re back—”
“Hey! This is somebody that ain’t got any business around here!” called a man from the machine shop corner of the improvised hangar. He had earphones on; he was listening to a detector a little like Benson’s only much less effective.
It had been effective enough, however.
“Strange plane!” he yelled again.
The man with the battered hat promptly forgot all about Nellie. He threw his cigar into the water, where it hissed and went out.
“Lights!” he yelled. “Everybody down. Douse the lights on the boat. Get tommy guns!”
Every light in the place winked out as the man near the diesel cut the switch. An instant later the lights on the cruiser went out, too.
“No, leave the doors open,” the man in the battered hat called as the hangar portals started to close. “Anybody coming this near must know something. We want to catch ’em, not just stay hid till they go away. With the doors open, they might be dumb enough to walk right in.”
Smitty, leaning bound against the hull, felt torment tear at him. He knew those motors. They were Benson’s. The chief was near here — coming here probably. And the place had suddenly and effectively been turned into a death trap—
The leader of this hell crew wasn’t dumb.
“Gag the big guy, and the girl,” he snapped.
Smitty got out one roaring yell as a man approached with a piece of dirty waste. But the warning was premature, he knew. It could never be heard on the plane, still far off, and insulated from sound by its own motors. Then the waste was gagging his lips; and Nellie was similarly silenced.
The giant could only sit there, sweating, with the knowledge that from every vantage point in the darkness the snouts of submachine guns pointed toward the hangar door. If the chief attempted to wade through there—
“Ye’re goin’ down to their hangar?” Mac said, in the big plane. “Why, if ye don’t mind the question?”
Benson’s dead, white face could never express an emotion. But his pale eyes looked as though they might have smiled a little.
“Even a ghost plane, Mac, has to have a hangar,” he said. “And the doors in the end of the ferry, I see, are open and inviting.”
“Then ye’re not only goin’ to land, ye’re goin’ into the ferry?”
Benson nodded.
“Ye’re goin’ to taxi the plane in?”
“Yes, Mac. And don’t ask why. The reason is obvious. The ghost ship disappeared near here. Maybe, as I said, even ghost planes can use hangars. But this one couldn’t use this hangar if another ship already plugged the room in it, now could it?”
Mac gnawed at his lip, and stared doubtfully at the innocently inviting hangar portal as Benson set the plane down on the water with a smoothness that few pilots could have equalled.
The big ship slid toward the ferry, slowed, spurted forward as the motors blipped.
In the dark hull, gun snouts poked forward with grim eagerness.
Benson slid the big plane into the hull with miraculous deftness, considering there was less than a yard of clearance at the end of each wingtip and less than a foot of clearance at the top.
The amphibian crunched gently to a stop on the slanting bottom of the ferry’s hull—
And lights burst out in every angle of the place.
At the same time the hangar doors began to close. The trap had been entered — and sprung.
But Smitty, the instant he had seen the chief piloting the plane in, instead of entering the place personally, had relaxed with a happy grin on his battered lips. And in an instant the gang in the ferry knew why.
Trapping that plane was a little like catching a tiger in a muskrat trap.
“This,” said Benson, with Mac in the pilot’s compartment, “is a little unexpected.”
“But a guid surprrrise,” burred the Scot. “Look — they got Smitty, the big numbskull. And ’tis here they came with Nellie. ’Twill be a nice party gettin’ them out of here.”
“We’ll loose a few of those special gas melons of yours, Mac—”
They couldn’t hear each other any more. The gang, inflamed with grim pleasure at the lucky fluke that had brought the enemy, plane and all, into their trap, had cut loose with every gun in the place. And for a moment they felt quite satisfied with the result.
Holes leaped into being in a dozen places in the all-metal wings and fuselage.
But only in part of the fuselage.
The pilot’s compartment was in a second metal shell, cupped within the fuselage proper, that could have turned even .50 caliber army machine-gun bullets. The submachine gun slugs were no more effective against it than so many dried peas.
They could and did drill the rest of the plane. But in there, Mac and Benson sat in serene safety.
Two glass spheres dropped from the rack under the fuselage. They hit only water; but they were so delicate that even that cushioned impact shattered them.
Within the glass melons was a gas of MacMurdie’s own clever inventing. It had such an affinity for oxygen that it rushed to fill the great cavern of the ferry in a quarter of a minute. It had such anaesthetic properties that the persons in there breathing it began to feel as if serpents coiled around their agonized throats, in another five seconds.
Not till then did the gangsters realize that their trap had been deadly only to themselves. Not till then did they see that their streaming slugs did no real damage; that slugs had passed through those wings before, and their passage been easily and quickly repaired by small duralumin disks fused over the holes.