The gangster was wrong. For Doc Savage was speaking one of the least-known languages in existence. The tongue of the ancient Mayan civilization which centuries ago flourished in Central America! And his words were going into the telephone!

When all the gangsters looked in the bedroom, they had given Doc sufficient time to call Monk at his skyscraper office. The thugs had been too excited to hear him whisper the phone number.

Doc was a ventriloquist of ability. He had thrown his voice into the bedroom to get the attention of his captors.

It would have surprised the absent leader of the thugs to know the hypodermic needle he had used on Doc had actually contained nothing more harmful than water! Doc had chanced to have the needle on his person. And he had slipped it up his sleeve for the purpose of deceiving the villains.

It was not the needle with which Doc made his enemies unconscious so mysteriously.

DOC SAVAGE continued to speak Mayan. The lingo sounded like gibberish to the listeners in the shabby room.

To homely Monk in the uptown skyscraper, however, it carried a lot of meaning. All of Doc's men could speak Mayan. They used it when they wanted to converse without being understood by bystanders.

"Renny, Long Tom, and Johnny should be there by now," Doc told Monk in the strange language.

The three men he had named were the remaining members of his group of five adventuresome aids!

"Tell Johnny to get the contents of Drawer No. 13 in the laboratory," Doc continued. "The contents will be a bottle of bilious-looking paint, a brush, arid a mechanism like an overgrown field glass. Tell Johnny to bring the paint and brush here."

Doc gave the address of the dive where he was being held.

"There are two sedans parked outside," the bronze man went on in the gobbling dialect. 'Tell Johnny to paint a cross on the top of each one. He is to bring his car which is equipped with radio. He is to wait in a street near by when he has finished the painting.

"Long Tom and Renny are to take the overgrown field glasses and race to the airport. They're to circle over the city in my plane, Renny doing the flying, while Long Tom watches with the overgrown glasses. The glasses will make the paint Johnny will put on the sedan tops show up a distinctive luminous color. Long Tom is to radio the course of the sedans to Johnny, who will follow them.

The gangsters were listening to the clucking words. Evil grins wreathed their pinched faces. They didn't dream the gobble could have a meaning!

"You, Monk, will visit the police station where the thugs who attacked Victor Vail and myself outside the concert hall were taken." Doc said. "Question them and seek to learn where a sailor called Keelhaul de Rosa would be likely to take Victor Vail.

"Ham is to remain in the office and question the rat you found unconscious in the laboratory, also seeking to find Keelhaul de Rosa and Victor Vail.

"If you understand these instructions, snap your fingers twice in the telephone transmitter."

Two low snaps promptly came from the wedged-up telephone receiver. They were not loud. Not a thug in the room noticed them.

DOC SAVAGE now became silent. He lay as though life had departed from his giant form.

"Reckon he's kicked the pail?" a crook muttered.

Another man made a brief examination.

"Naw. His pump is still goin'."

After this, time dragged. The guard outside the door could be heard. Once he struck a match. Twice he coughed hackingly.

A gangster produced two red dice. The men made a pretense at a crap game, but they were too nervous to make a success of it. Seating themselves in the scant supply of chairs, or hunkering down on the filthy floor, they waited.

Doc Savage Was giving his men time to get on the job. Johnny would have to daub the luminous paint on the sedans. Renny and Long Tom would have to arrive over the city in the plane. Twenty minutes should be sufficient time.

He gave them half an hour, to be sure. Indeed, his keen ears finally detected a series of low drones which meant the plane was above. Doc's plane had mufflers on the exhaust pipes. Renny was evidently cutting the mufflers off at short intervals to signal his presence to his pals.

Doc rolled over. He did it slowly, like a sleepy man. He now faced the hallway door.

The thugs tensed. They drew their pistols. They were as jittery as a flock of wild rabbits.

Doc imitated the raucous voice of the guard. He threw it against the hall door.

"Help!" the voice yelled. "Cripes! Help!"

The guard outside heard. He might have recognized his own tone. Maybe he didn't. He wrenched the door open, at any rate.

The instant his ugly face shoved inside, Doc threw words into his mouth. The guard was too astonished to say a word of his own.

"De cops!" were the words. "Dey're on de stairs! Lam, youse guys!"

Pandemonium fell upon the gangsters. They rasped excited orders. They actually squealed as though they were already caught.

One man saw the giant bronze figure of Doc Savage heave up from the floor. He fired his pistol. But he was a little slow. Doc evaded the bullets. He reached the light switch, punched it.

Darkness clapped down upon the room.

"De cops are inside!" Doc yelled in the guard's voice. "We gotta lam, quick!"

To make sure they fled in the right direction, Doc glided over and kicked the glass out of the window.

"Dis way out!" he barked.

A thug sprang through the window. Another followed. Then a succession of them.

Standing near by, Doc darted his hands against such faces as he could find in the black void. Three men he touched in this manner. Each of the three instantly dropped unconscious.

The others escaped from the room in a surprisingly short space of time.

Doc listened. He heard both sedan engines roar into life. The cars streaked away like noisy comets.

INTO THE room where Doc Savage stood there now penetrated a weird sound. It was low, mellow, trilling. It was exotic enough to be the song of some strange bird of the jungle, or the eerie note of wind filtering through a jungled forest. It was melodious, though it had no tune; it was inspiring, without being awesome.

This sound had the peculiar quality of seeming to arise from everywhere within the shabby room, rather than from a definite spot.

This trilling note was part of Doc — a small, unconscious thing which he did in moments of emotion. It would come from his lips as some plan of action was being arranged. Sometimes it precoursed a master stroke which made all things certain. Or it might sound to bring hope to some beleaguered member of Doc's adventuresome group.

Once in a while it came when Doc was a bit pleased with himself. That was the reason for it sounding now.

Doc turned on the lights. He lined up the thugs he had made unconscious.

Eleven of them! It was not a bad haul.

Doc used the phone to call Ham at the scraper aerie uptown.

"You might bring your sedan down here," Doc requested. Ten minutes later, Ham came up the rickety stairs, twiddling his sword cane. Ham's perfection of attire was made more pronounced by the blowsy surroundings. He saw the pile of sleeping prisoners.

"I see you've been collecting!" he chuckled.

"Did you get anything out of Keelhaul de Rosa's man?" Doc asked.

"I scared him into talking," Ham said grimly, "but the fellow was just a hired gunman, Doc. He and his gang were hired to get Victor Vail. They were to deliver the blind violinist to Keelhaul de Rosa, right enough. But the delivery was to be made on the street. The man had no idea where Keelhaul de Rosa hangs out."