"You are becoming one of my most trusted and efficient servants," he told Buck Boontown.
   "Oui!"
   mumbled the swamp man, highly pleased. "Tank yo'!"
   "I now have a most important task for you to perform."
   "Oui!
   I do heem fo' yo'!" At the moment, ignorant Buck Boontown was so impressed he would have laid down his life at a mere word from the sinister devil who held sway over him.
   The Gray Spider now produced a chamois poke of the type used by stores to deliver their cash to the banks. This was weighty with silver coin.
   It held exactly one hundred dollars!
   Buck Boontown clutched the poke eagerly. In common with most barbaric folk, a pile of silver coins gave him a bigger kick than ten times the sum in crisp bank notes.
   "This is your reward," said the Gray Spider. "It is your pay for what you are to do. Later, if you serve me properly this time, there will be other tasks for you—and more rewards such as this!"
   Buck Boontown could only mumble his gratitude.
   The Gray Spider held up the hand on which the hideous tarantula constantly crawled.
   In answer to the signal, two swamp men now carried in a box the size of a small trunk.
   "Do you know what these are?" asked the Gray Spider.
   Buck Boontown stared at the box contents. He seemed puzzled and disappointed.
   "Flies!" he muttered. "Dey ees plain beeg o' flies!"
* * *
   THE swamp man's disappointment gave the Gray Spider great delight. An explosive chuckle fluttered the silk folds of his mask.
   "They look perfectly harmless, eh?"
   "Oui!
   Dey like a bite a man. But dey no do heem any harm."
   A fresh guest of hideous mirth emanated from the Gray Spider.
   "There's where you're wrong, swamp boy!" he declared. "These are very special flies. If one of them should bite you, it'd kill you instantly."
   Buck Boontown looked as if he found this hard to believe.
   "These look like ordinary swamp flies because they were just that—before I got hold of them," the Gray Spider explained. "I have sprayed a very powerful poison upon them. The bodies of the flies have absorbed this poison, which has no effect on them. But their bites are now highly venomous. They will bring instant death to a man."
   "
   Sacrй!"Buck Boontown gulped.
   The Gray Spider leered. "Making these flies poisonous is a very special secret of mine. It took me a long time to figure out a way of doing it. But I'm telling you, it works!
   "Furthermore, I have starved these flies until they're famished. They live by sucking blood. They'll go after any living thing that's handy when they're let out of that box. And whatever they bite will die!
   "You are to release them near the bronze devil and his five men."
   Buck Boontown wrinkled his forehead. "Oui! But won't de flies bite and keel me, too?"
   "You'll set a clockwork so it'll open the lid," explained the master fiend. "You merely take the box near the bronze man's trenches and dugouts, and set the clockwork to open the box at dawn. Then you have all the swamp men clear of the vicinity. The poison flies will do the job for us. You savvy?"
   "Oui!"
   Buck Boontown agreed.
   He received detailed instructions on how to operate the clockwork. Then he departed from the Castle of the Moccasin, carrying the box of venomous flies on his back.
   The journey back to where Doc Savage and his five men were beseiged was a tedious one. It took Buck Boontown until long past midnight.
   He exchanged a word with his men, telling them to quit the vicinity.
   "Yo' keed, Sill, ees come back," offered the one to whom he talked. "Hees wit' yo' wife."
   Buck Boontown was overjoyed at this news.
   He quickly placed the box of deadly flies. He set the clockwork. At the hour of dawn, the venomous insects would be freed.
   Doc Savage and his men would not suspect the innocent swamp flies of being poisoned. They would be bitten by the famished horrors. And death would come!
   Buck Boontown hurried away to meet his wife. He wanted to see his son, Sill, whom he loved deeply. Poor, unfortunate Sill! Perhaps, some day, when they went to the wondrous New Orleans to live, a great doctor could do something for Sill.
   The swamp man did not know that he had just sentenced to death the man who had already, by his magical skill, made Sill a normal youth.
* * *

Chapter XVI. THE PAY-OFF

   BUCK BOONTOWN paused several times to question such retreating swamp men as he encountered. He made sure all were getting away. None had been missed in spreading the word to quit the vicinity.
   Doc Savage and his five men, Buck Boontown was assured, did not suspect a general exodus was under way.
   "At dawn, dey weel die!" the swamp man leered.
   He went on. The women and children of the voodoo clan had been moved to a spot a mile distant. He reached the place.
   Every one was gone.
   He spent twenty minutes learning the women and children had moved on a couple of miles. He tramped after them.
   Somewhere in the distance, a rooster was crowing in a swamp henhouse. The hooting of owls had died. The eastern sky was showing ruddy color. Already, the higher clouds were being tinted like patches of gore by the first rays of the sun.
   Dawn was not far off.
   Buck Boontown joined his wife and son.
   "How ees de keed?" he asked his wife.
   "I'm all right, dad," said Sill Boontown.
   Something in the lad's tone gave the swamp man an inkling of the truth. A great elation came into his wizened face. The shining happiness in his wife's features convinced him that what he had hoped for had come to pass.
   The story quickly came out. Sill Boontown told of the operation which had worked such a miraculous cure.
   Finishing, the youth produced several folded bank notes.
   "De bronze man geeve me dese," he explained.
   "What fo'?"
   "Hees say fo' me to pay my way t'rough school een New Orleans with de money," replied the boy.
   Buck Boontown looked at the denominations of the bills. He totaled their sum laboriously. The amount his son held exceeded by many times the pittance the Gray Spider had handed out for having murder done!
   Remorse seized Buck Boontown.
   This mighty bronze man who pursued the Gray Spider was not the devil he had been painted! He did not mean to slay all the worshippers of voodoo—for it was such a bloodcurdling lie that the Gray Spider had spread.
   The bronze man had given Buck Boontown back his son—magically returned to normalcy.
   Moreover, he had furnished the boy with money to educate himself, to visit the wondrous city of New Orleans. He had given a sum greater than Buck Boontown had ever expected to save!
   These thoughts formed a dizzying maelstrom in the swamp man's head. And towering black and ghastly over it all was the knowledge that his hand was sending death to the giant bronze man.
   Buck Boontown was not rotten at heart. His surroundings had made him ignorant and cruel. Raised in a civilized community, he would unquestionably have been respectable.
   With a loud moan, Buck Boontown whirled and ran. He knew what he must do!
   He made directly for the mound where Doc Savage and his five men were beseiged.
   The swamp man hoped to get there in time to stop the escape of the flies, the bite of which would be fatal. His was indeed a race with death.
* * *
   BUCK BOONTOWN threw away his machine gun. He also discarded a revolver. He was getting rid of all excess weight.
   He sloughed through lakes of slime that he would ordinarily have gone around. Jabbing, scratching thorn thickets failed to turn him. He took perilous chances with a muddy bayou infested by 'gators.
   The sun was nearly in view. Light of a beginning day seeped into the clammy, moist jungle.
   It was almost the exact hour set for the opening of the box which held the poisonous insects.
   Buck Boontown sought in vain to put on more speed. He rolled from side to side with exhaustion. Each tremendous, explosive breath blew a spray of crimson off his lips, for he had bitten through his tongue.
   The mound where Doc and his five men were beseiged came into view.
   Buck Boontown veered to the right. He saw the box which held the venomous flies. Horror gripped him anew.
   He was too late!
   The box lid was opening!
   The swamp man did not slacken his headlong pace—he even managed to go a little faster. He pounced upon the box. A scant dozen of the poisoned flies had as yet escaped.
   Buck Boontown knew the price he was going to pay for what he was doing. He did not hesitate. His was a man's code, for all the fact that he had fallen under the hideous spell of voodoo. Doc Savage had returned sanity to his son—therefore he would save the giant bronze man from this death trap.
   One of the venomous flies bit him even as he closed the box lid. He hardly faltered. He secured the lid. Then he sat down on the box.
   Deliberately, he let the famished, deadly flies settle upon him and begin drawing his blood.
   Then he mashed them, one at a time!
   After the destruction of the last devilish insect which had escaped, Buck Boontown got off the box.
   Doc and his five men watched the swamp man's staggering approach.
   "What ails the guy?" Monk muttered.
   They soon learned the answer to that. Gasping, Buck Boontown explained. His words got weaker, incoherent. His face purpled. The deadly poison was working like cobra venom.
   "Where is this Castle of the Moccasin?" Doc demanded.
   Buck Boontown knew he was dying. Perhaps he saw the hideous falsity of the deities of voodoo. Perhaps he realized at last that the Gray Spider was a fiend lower than the water moccasins, the likeness of which he tattooed on the mouth roofs of his slaves. Whatever moved the swamp man, it was a force for the good of humanity.
   In two strangled gasps, he told where the Castle of the Moccasin was.
   Then he fell dead.
   Buck Boontown had paid off.
   A heavy silence held the little group of adventurers for a time. They couldn't think of anything to say.
   Finally, Monk voiced a thought as good as any.
   "That guy," said Monk, "was a hero!"
* * *

Chapter XVII. "THE GRAY SPIDER IS—"

   SULTRY midday heat pressed upon the Castle of the Moccasin. Living steam poured up from the soggy jungle of the great morass. Even the mocking birds and the blackbird and the cardinals hung listlessly in the festering vegetation, emitting cries that were only croaks. The little lizards that usually darted up the palmettos so swiftly now set a pace that barely crawled, or hovered panting under a spiked frond.
   It was as though the odious presence of the great, sinister, hidden castle of stone had contaminated and sickened the surrounding swamp.
   But inside the Castle of the Moccasin there was an air of evil jubilation, awaiting good tidings.
   The Gray Spider himself paced circles around his gilded throne in the room of crazy coloring. He tossed his lead-colored tarantula playfully in the air and caught the repulsive thing as it came down. He still wore his mask of silk and the snake-embroidered gown.
   "What's keepin' them slowpoke swamp snipes!" he growled impatiently. "They should've had a messenger here before now, tellin' me the bronze devil and his five nosey pals have kicked the pail."
   Up sailed the awful tarantula, its many legs kicking. The man in the robe and mask caught it with a flourish.
   "Probably the swamp snipes were afraid to go near enough to see if they were dead," he decided. "I'll get the news before long."
   He strode jauntily to the outer door.
   "Go tell the guards to rush any messengers right inside," he ordered the watchman who stood at the portal.
   "Oui!"
   said the watchman.
   The Gray Spider went back inside.
   The watchman started off on his errand. He entered the tangled swamp growth.
   Suddenly he stopped. Something had hit his chest. It made a dull, mushy sound. He looked down. He saw fragments of glass clinging to his shirt front. They looked like parts of a thin-walled glass ball. It had contained some kind of liquid. He smelled a faint, strange, rather pleasant odor.
   Then he went to sleep.
   "Them anaesthetic balls sure work like a charm!" chuckled Monk, stepping out of the near-by jungle. He disarmed the man.
   "This seems to be the last of the guards," clipped Ham. He came into view, gave his sword cane a flourish, and added: "The other three were no more trouble than this one was. Aren't we going to get the satisfaction of a fight out of this?"
   "What d'you know about fighting?" Monk leered pleasantly.
   "Pipe down, you guys!" suggested Doc.
   Renny, Johnny, and Long Tom stood behind Doc. They looked like a giant and two skinny dwarfs back of a big bronze statue. Not that Johnny and Long Tom were runts when compared to men of ordinary stature. They were simply in big company.
   "Let us see what the future holds, brothers," Doc suggested mildly.
   They came out of the jungle. Before them towered the Castle of the Moccasin.
   "I wonder how you get in?" Ham puzzled.
   "I'll get you in!" Monk said grimly.
   He drew a hand grenade, plucked the pin and threw it. The metal egg sailed against the vine-clad walls of masonry.
   It hatched a devilish red sheet of flame. Solid stone turned magically into dust, smoke and a shower of fragments. The roar of the exploding nitro bumped in deep salvos across the matted swamp.
   A great hole gaped in the wall of the Castle of the Moccasin.
* * *
   DOC and his men charged the breach. They vaulted tumbling blocks of rocks. They doubled low and bored through acrid smoke and blinding dust.
   A vast room lay before them. The color scheme was repellant. It consisted of daubs and streaks and splotches of every imaginable hue. It was an ugly room, garish, cheap. Colored lights blinked like evil eyes.
   A big and flashy throne occupied the middle of the floor.
   Across the room, a man in a silken mask and a robe embroidered with snakes was just dodging through a door. The panel slammed. It locked.
   "There he goes!" Renny bawled in a voice that was like thunder in a barrel.
   Doc and his men pursued the Gray Spider.
   Halfway across the room, Monk stopped to jump with both feet on the Gray Spider's repulsive, lead-colored tarantula. The thing had been dropped by the master fiend in flight, and was scuttling circles on the floor.
   "I hope that's an omen!" Monk grinned as his big feet squashed the vile thing.
   They hit the door. It was of wood. Renny's machine gun made a noise like a steam riveter gone wild.
   Renny was a good machine gunner. He could not have cut the lock out of the door more neatly with a keyhole saw and an hour in which to work.
   The door whipped open.
   "This way!" breathed Doc. His sensitive ears had picked up the Gray Spider's shuffling feet.
   They went down a corridor. Stairs sloped into the innards of the earth.
   Doc took the stairs with incredible leaps that covered fifteen steps at a time. He placed his feet in the mathematical center of the treads upon which he landed, as though he had been stepping down one at a time.
   Monk sought to imitate Doc's feat. He met disaster. Head over heels, he flopped down the stairs—only to gain his feet no more damaged than had he been a man of rubber.
   "Graceful as usual!" sneered Ham.
   "Yeah!"
   The deafening cackle of a machine gun drowned Monk's comeback. Bullets chiseled rock chips off the corridor sides.
   Renny's rapid-firer snapped spitefully—twice. The passage went silent, except for the bang of racing feet and the snorty breath gusts of men in action.
   The Gray Spider was proving fleet, now that death was blowing frosty breath down his neck.
   The stairs leveled out in another passage. This one had steel-grilled doors on either side. It resembled the corridor in a penitentiary cell house.
   Faces were pressed to the bars!
   Doc caught a glimpse of the attractive features of Edna Danielsen. A moment later, he saw Big Eric.
   Fat Horace Haas was also there, with his flashy clothes sadly bedraggled.
   This was the Gray Spider's prison! Here he held the owners of the great lumber companies of the South and tortured them into doing his bidding—doing such things as signing control of their concerns over to men who were tools of the Gray Spider.
* * *
   THE chase led into another room. This was fitted with a desk, calculating machines, many big sheet-metal filing cabinets.
   The cloaked and masked Gray Spider was tearing at a door across the chamber. He had grasped up a handful of notebooks and papers in his flight.
   He dropped the documents in his wild haste. He got through the door barely ahead of Doc's flashing bronze form. The door slammed. This one was of heavy steel. The lock tumblers rapped over.
   Doc Savage scooped up the papers the Gray Spider had dropped. He ran backward.
   "Lay an egg!" he clipped at Monk.
   Monk hauled a hand grenade out of his capacious pockets.
   "Holy cow!" choked Ham, remembering Monk's headlong fall down the stone stairs. "And your pockets were full of them things!"
   Doc Savage eyed the documents he had seized. They were a find indeed!
   They seemed to be a complete record of the Gray Spider's crooked transactions, as well as the roster of his organization. There was proof enough here to send every man of his vile gang fleeing from justice.
   Monk's hand grenade exploded. The steel door caved like a tin can hit by a shinny stick. It appeared to float off its hinges.
   Doc and his men barged through.
   Unexpected resistance met them.
   In a vast room, thirty or so yellowish-brown men milled. They were members of the inner circle of the Cult of the Moccasin. Every man was armed.
   It was evident they had been holding some kind of a conclave. In the center of the chamber stood a box. It had large holes for ventilation. These were covered with a fine screen.
   A box of the poisonous flies! Evidently the Gray Spider had more of the things on hand, in case his first batch didn't work.
   The members of the inner circle must have been examining them.
   A pistol rapped. The bullet stirred Doc's bronze hair—which, remarkably enough, was thus far no more ruffled than it would have been by a Waldorf banquet.
   Renny's deadly machine gun burred loudly. The pistol wielder gave an imitation of a sack emptying itself.
   But the fight was not going to be won with a shot or two. Several of the voodoo men were lifting machine guns.
   The Gray Spider had taken shelter behind them. Suddenly his purple-veined talon whipped up. It flung a hand grenade.
   The deadly blow of metal flew straight
   Doc and his men seemed doomed. The sportiest gambler wouldn't have bet a slot-machine slug on their chances. They had no time to retreat. You couldn't hurl back this type of grenade. They exploded the instant they reached you. And there was enough nitro in it to reduce all five men to mangled fragments.
   As on countless other occasions, it was the giant bronze man who saved the situation.
   With a speed no eye could have caught, Doc's hand swept over. It plucked Renny's machine gun from his big hands. The weapon flashed through the air.
   It was a perfect throw. The hurtling machine gun met the grenade.
   The grenade exploded near the box which held the poisonous flies. That box was ruptured.
   The deadly insects swarmed out.
* * *
   "Back!" Doc's powerful voice throbbed. "Get out of here!"
   He and his men turned heel and fled from the buzzing death flies. Behind them, men screamed. The famished insects were settling upon them. They were falling victim to their own murderous tool.
   Of all the fiends left behind in the room of death, only the Gray Spider had the presence of mind to try to flee by the same route Doc and his men had taken.
   He pounded after Doc, a score of feet to the rear.
   The evil master knew the fly stings meant his finish. He screamed as the small creatures bit into his flesh; he tried to beat them off his face, tearing off the gaudy silk covering that served for a mask.
   It was then that Doc and his men saw the features of this man who called himself the Gray Spider, They had reached the end of the passage, were going through the door which closed off the barred cells.
   Just as they were about to step through, the screaming maniac behind them tripped on his own long robe, fell head-foremost on the floor. The bloodthirsty, poisonous flies swarmed about his distorted features, inflicting death with every thrust.
   Only a moment did Doc and his men look at that agonized face; only a moment was needed to recognize the features of this master devil who plotted so skillfully, with such dire cruelty.
   In that moment, Doc and his companions in adventure saw the one person whom few would suspect. It was the face of Silas Bunnywell—and the screams were the voice of Silas Bunnywell, the voice which, a short while ago, they recognized as having heard before.
   Silas Bunnywell, old and decrepit bookkeeper for Big Eric's concern, was the Gray Spider!
   With a mighty slam, Doc shut the door upon the leader and the ringleaders of the Cult of the Moccasin. The death they had planned for others would be fit punishment for themselves!
* * *
   IT took but short minutes to unlock the barred cell doors. They found a ring of keys on a peg near the corridor end.
   Pitiful indeed was the array of prisoners who stumbled forth. Some had been there years, their sobbed testimonials of delight and gratitude disclosed. The Gray Spider, it seemed, had been operating a long time, and only of late had become bold enough to throw his insidious web about the largest lumber companies of the South for the grand cleanup.
   Most moving of all, perhaps, was the simple statement of thanks which beautiful Edna Danielsen gave Doc Savage as the bedraggled cavalcade quitted the Castle of the Moccasin. The gripping part of her expression was not the commonplace words, but the depths of feeling that went into them. There was a sort of joy and hopelessness intermingled—as though she finally understood that she must keep hidden forever the emotions her heart held for the mighty man of bronze.
   Monk expressed it. He usually had a description for everything.
   "It's tough for her to fall like that," said Monk. "For the woman isn't made who can get a rise out of Doc."
   * * *
   OUTSIDE, in the steaming sunlight of the swamp, tension fell from the adventurers. Their work here was done.
   Standing a little apart, the giant bronze man looked thoughtfully into the north.
   He was thinking of the face of the Gray Spider, the face of the old bookkeeper—Silas Bunnywell—as he lay on the floor, victim of his own evil!