The warriors hurried to obey. They returned, bearing long strings of the tough hide.

"Fear him not!" said the serpent man. "My magic breath has stricken him, so that he will lie helpless for two hours."

The fellow had profited by talking to the victim of Monk's gas. He had learned about how long its effects lasted.

"I shall go now to send my magic breath into the interior of the pyramid!" snarled the snake man. "Six of you remain here and bind the bronze devil. Bind him well! Death shall strike all six of you if he escapes! He is to be sacrificed to the Feathered Serpent."

With that warning, the fellow departed, the long, feather-studded snake tail scraping behind him. He was even more sinsiter than the reptilian monster after which he was disguised.

He moved from view.

The six evil Mayans seized their festoons of tapir-hide thongs and leaned over to lay violent hands on Doc. They got the shock of their lives.

Steel talons seemed to trap the throats of two. Another pair bounced away, driven by pistoning bronze legs.

At no time had Doc Savage been unconscious. Monk's remarkable gas depended for its action upon inhalation. Unless some of it penetrated to the lungs, the stuff was quite ineffective.

Because of his conscientious exercises, Doc had lungs of tremendous capacity. An ordinary man can, by straining himself, usually hold his breath about a minute. Several minutes is not uncommon for pearl divers in the South Seas. And Doc Savage, thanks to years of practice, could hold his breath fully twice as long as the most expert pearl diver.

He had held his breath all the while the snake man was waiting for the gas fumes to blow from the stone house.

By this ruse, which only he could manage, Doc had escaped being shot on the spot.

Doc shook the two Mayans whose throats he held. He brought their heads together, knocking their senses out. The other two were tangled in the tapir-hide strands, trying to reach their obsidian knives.

Using the two men in his hands as human clubs, Doc beat the others down. The two his powerful legs had knocked away had collapsed where they fell.

A single piercing squawl of agony, one warrior managed to emit. Then all six were sprawled unconscious in the stone-paved street.

Doc straightened. Into the stone house be leaped. He would only have a moment. That yell of the red-fingered man would spread an alarm.

The metal case which contained Monk's chemicals was not behind the stone bench where Monk had kept it.

Doc was disappointed. He had hoped to get enough chemicals to rig up gas masks effective against Monk's remarkable vapor. But the snake man had evidently appropriated the chemicals.

Out of the building, Doc ran. A machine gun blasted at him from down the narrow street. But it was poorly aimed. The slugs went wide.

Before the serpent-skin-clad man — it was he who had fired — could correct his aim, Doc's metallic form had vanished like smoke. It seemed to float to a building top.

To another roof, Doc leaped, thence onward. Dropping down into a street, he ran several hundred feet.

There, he purposefully let the red-fingered crew glimpse him. He disappeared with lightning speed before they could fire. Howling like a wolf pack, they rushed the spot.

Dozens of them quitted the siege of the pyramid to aid in the chase.

That was what Doc had maneuvered for. It was imperative that he get back into the pyramid and devise something to defend the Mayans against the gas now in the possession of the fiendish warrior sect.

Unseen by any, Doc raced for the pyramid. So silently did he come, and so swiftly, that he was gliding up the steps before they saw him. And then it was too late.

A machine gun cackled angrily. Lead ricocheted off the steps, or splattered like raindrops.

But Doc was already up the stairs and inside the pyramid. Even Renny and the others were a little startled at the suddenness of his appearance. They were awed, too. It was near unbelievable that even Doc could go and come as he had, with four alert machine guns emplaced about the pyramid.

"They have secured Monk's gas," Doc explained. "They'll try to toss bottles of it into the secret doorway exposed by moving the idol."

"Then we'll move the idol back!" Monk grunted.

Straightway, exerting his enormous strength, Monk shifted the massive stone image of Kukulcan back.

A light sprang up below. One of the Mayans had lighted a torch. This was composed of a bowl filled with animal oils and equipped with a wick, not unlike an ordinary lamp. Evidently it had been placed in this weird place for just such an emergency.

"Chink the cracks with mud," Doc directed. "They'll break the glass bottles of the liquid that makes the gas, hoping it will seep inside."

"But what about our peepholes!" Renny objected. "We can't see them if they start up the stairs!"

For answer, Doc reached over and took off Johnny's glasses which had the powerful magnifying lens on the left side.

"Use the right glass — the one that does not magnify," he suggested. "Pack mud around it, and where could you find a better porthole. It will keep the gas out."

"Dag-gone!" Monk grinned. "I don't believe anything will ever stump Doc!"

The Mayans were string about below. Hundreds of them had gone into the pyramid, Doc reflected. There must be something in the nature of an underground room, or perhaps passages below.

"If they throw the gas bottles," Doc told Renny, "they won't rush the steps until they know the fumes have blown away. So when you see them coming, you'll know it is safe to open the secret door and roll rocks down the stairs. You can tell the Mayans to pass up rocks, using sign talk."

"Where you goin'?" Renny wanted to know.

"To explore. I am very curious about this place!"

Chapter 20. GOLDEN VAULTS

Doc Savage took Johnny and Monk with him as he wended into the depths of the golden pyramid.

He was surprised at the amount of wear the steps underfoot showed. In spots, they were pitted to half their depth. It must have taken thousands of human feet to do that.

The sovereign of the Mayans, King Chaac, had said only he knew of the existence of this place. That meant it had not been used extensively for generations — possibly not for hundreds of years. For information about a place such as this would be handed down from father to son for ages.

At a spot which Doc's expert sense of distance told him was several feet below the surface of the surrounding ground, they entered a large room.

Doc noted a cleverly constructed stone pipe which bore the water that fed the pool on top of the pyramid. This crossed the room and vanished into another, larger chamber beyond.

This latter was a gigantic hallway, narrow and low of roof, but of unfathomable length. In fact, it was more of a tremendous tunnel. It stretched some hundreds of yards, then was lost in a turn upward.

Down the middle of it ran the finely constructed stone conduit carrying water.

In this subterranean corridor, King Chaac and pretty Princess Monja waited with their subjects.

The entrancing young Mayan princess had retained her nerve remarkably well during the attack. Her golden skin was a trifle pale, but there was no nervousness in her manner.

King Chaac was maintaining a mien befitting a ruler.

Doc drew the aged Mayan sovereign aside.

"Would you care to guide Johnny and Monk and myself into the depths of this cavern?"

The Mayan hesitated. "I would, gladly! But my people — they might think I had deserted them in their need."

That was good reasoning, Doc admitted. He had about decided to go on alone with Monk and Johnny when King Chaac spoke again.

"My daughter, Princess Monja, knows as much of these underground passages as I do. She can guide you."