Johnny settled behind an aromatic magnolia shrub and listened. He could hear cars honking occasionally on distant Gentilly Road, and on nearer park drives. Behind him, to the south, the lights of the New Orleans business district made a vast glow in the steaming night.

Suddenly there reached Johnny's ears a series of droning noises. It was as if some one were holding a bumble bee near by, and letting it buzz its wings at intervals of a half minute or so. The sound came closer. Johnny recognized it.

"A seaplane taxiing along the lake edge!" he decided aloud.

Soon the buzzing quality left the motor spurts. They became violent hisses. The exhaust had been cut into mufflers.

"Doc's speed job!" Johnny concluded. "It's the only craft I know of fitted with silencers."

He grinned. Doc was going to get him into the swamp by plane! That would simplify things.

Johnny knew Doc must have had floats installed on the big speed ship during the afternoon. The craft was equipped for quick installation of a type of float commonly carried in stock by large plane-supply concerns.

Boldly, Johnny advanced for the lake edge.

He did not expect danger. He knew positively he had not been trailed here. So he took no pains to muffle his footsteps or keep to the shadows.

That was a mistake.

Swi-s-h!

Something sailed out of the blackness beneath a near-by tree. It settled on Johnny's neck. It tightened. It jerked him from his feet.

Johnny clawed at the thing that had him. It was a lasso of thin piano wire. It yanked again, digging into the flesh of his throat.

Three scrawny swamp men pitched from the murk beneath the tree. One flashed an ordinary cane knife which was honed like a razor.

"Non!"

gritted one of his fellows. "Gray Spider ees want talk to dis scamp!" He knocked the knife aside.

Johnny kicked a man in the middle. He booted so hard that he distinctly felt his heel push a stomach in and jar against a backbone. The fellow sailed ungracefully away.

A club rapped Johnny's head, causing a burst of colored lights and lances of flame. That, and the wire drawing steadily tighter around his neck, sapped his strength. His struggles weakened. They became slower. He was like a clockwork toy that was running down.

"Bien!"

puffed one of the Gray Spider's swamp men. "Eet ees about over!"

It was. But not like the swamp man expected.

There suddenly wafted over the scene of strife an uncanny trilling note. It was a whistle, and yet not a whistle. It had a low and mellow quality that might be likened to the song of some rare bird of the jungle, or the melodious but untuned note of a wayward breeze filtering among the pipes of a great organ.

It seemed to come from everywhere.

Johnny heard it, although but half conscious. The sound of Doc Savage!

THE sound had a remarkable effect on Johnny. Renewed energy flowed into his faltering muscles. He struck and flailed fiercely.

Out of the night came flashing a mighty bronze form. The charge of a lion would hardly have been more disastrous to the Gray Spider's two men.

Only two blows, coming so close together that they sounded like two men clapping hands simultaneously, and the pair went tumbling like rabbits shot on the run. It was doubtful if either had seen what caused their downfall. The third man, disabled by Johnny, writhed and moaned near by, entirely helpless.

Doc freed Johnny's neck from the wire noose.

"You're a handy guy to have around, Doc," Johnny laughed shakily. Then he noticed that the seaplane still taxied out on the lake. It was nowhere near shore. "Huh—I thought you were in the plane."

"Ham is flying the bus," Doc explained. "It occurred to me after you called that the Gray Spider might be doing some wire-tapping himself. In that case, he might have heard us make the appointment to meet here. So I dropped around merely to play safe. And here we are."

"Yeah—thanks to you," Johnny said wryly, feeling his sore neck. "One thing that is fortunate—on my call to you I didn't say a thing which would give the Gray Spider a clue to my identity or purpose."

"Sure—there's no harm done," Doc agreed. "In fact, we've added three more prisoners to our menagerie. Every little bit helps."

The plane now taxied close in. Ham, slender and waspish, waded ashore. He held his sword cane high over his head and said some uncomplimentary things about the mud underfoot.

"You are to take the plane into the swamp," Doc told Johnny. "Park it at some spot where nobody’ll find it. Use the radio to get in touch with me. Long Tom has installed a receiving and transmitting station in it. You will, of course, use the Mayan language, so no one will understand our talk."

"Righto," Johnny agreed.

"There's some stuff in the ship that you might need," Doc added.

Johnny now waded out to the plane, hauled himself up on one of the newly installed metal floats, and sprang into the cabin. The silenced motors sped up. The propellers churned the air shrilly. Out across Lake Ponchartrain, the craft streaked, then leaped into the air.

Johnny banked for the swamp country. He was an expert pilot, thanks to the teaching of Doc Savage. The remarkable bronze man seemed gifted with the ability to impart much of his own vast knowledge and skill to those whom he taught, and it was this strange quality which had turned his five friends into accomplished airmen, second only to Doc himself.

THE foggy area proved to be only in the vicinity of New Orleans. Johnny soon left it behind. He kept the silencers on the motors, made the cabin airtight, turned on the apparatus which supplied artificial air, and flew very high—about twenty-five thousand feet. He used powerful binoculars to observe the terrain below.

A narrow bayou wound like a frayed silver ribbon through the marshy jungle which looked from that height like so much green velvet. Johnny observed a few tow steamers escorting long, flexible log rafts.

An occasional sawmill town made a spotty patch of lights. These sawmill towns differed from other settlements in that they were always scattered about a group of mill buildings—sawing structure, kilns, rough-dry and finish storing sheds, planing mill, machine shops, and other shacks.

The sawmill towns became scarcer. Riverlike bayous, the only avenue of transportation in the swamp, ceased to gleam in the moonlight. Tall trees suitable for timber also became scattered.

Johnny knew he was over the wildest portion of the great swamps. He cut the ignition switches of the three motors. He threw a lever. This changed the characteristics of the plane wings, giving the remarkable craft a less steep gliding angle and a much slower landing speed.

The great ship settled upon the swamp like a monster bat with wings outstretched and paralyzed.

Johnny selected a tiny bayou. It resembled a spot where a huge finger had scraped away the festering layers of swamp vegetation, revealing the shining surface of a mirror. The mirror, of course, was water.

Lightly, the plane dunked its floats in the water. It coasted ahead. The wake it left fanned outward, seeming to throw the bayou into shimmering convulsions.

"If I just don't hit the bank too hard!" Johnny muttered.

He didn't. The ship grounded with a slight jar, after sloughing through tall cane and under heavy overhanging branches.

Johnny clambered out. Walking along the wing, he pulled down armloads of the clammy aлrial moss from the vines and drooping branches overhead.

This moss was the variety called "old man's beard" by the natives. Johnny used it to cover the wings and fuselage of the plane, so there would exist less likelihood of its being seen.