"What have you learned?" the young woman questioned him.
"Don"t ask so many questions," Doc said shortly.
Tip looked indignant. She was a very attractive bit of femininity, and obviously unused to mere males giving her short answers. During the past two days, she had seen a great deal of Doc. Her admiration for the bronze man had increased to a marked degree.
Doc Savage had noticed this with no delight at all. He could read signs. The young woman was falling in love with him, and there were no provisions for feminine entanglements in Doc"s perilous career.
"You don"t need to be snippy about it!" Tip told him peevishly.
"This work is highly technical," Doc said patiently. "As you know, I"ve been going over the recordings of instruments planted by Long Tom and Johnny. Furthermore, you"d need a lengthy course in electricity and geology before you"d understand any detailed explanation."
"Oh, all right!" said Tip, and flounced from the room.
Doc went on with his work.
He had received no word about the fate of his five men. No threat had come from the First Little White Brother. This in itself was an ominous portent.
Search as he might, Doc had been unable to get a trace of where his friends were held-if they were still alive.
The door flew open suddenly. Tip Galligan appeared, crying: "Look what just came in!" In both her shapely hands she held Monk"s homely pig, Habeas Corpus. Around the shoat"s neck was a leather thong. To this was tied a tiny bundle of cloth.Doc Savage whipped forward. Habeas Corpus had disappeared at the time Monk and the others were seized.
Habeas, the world"s homeliest pig, had no doubt been captured along with his owner.
Doc plucked the little bundle of cloth out of the thong. He unwound it. There was paper inside-a note.
YOUR friends!" pretty Tip Galligan gasped. "They sent the pig to you with a note!"
Doc spread the missive out. It read: We are being held in the Canyon of the Red Llama. A map will show you its location. We are locked in an abandoned mine located where the canyon narrows to a gash-a place called the Red Llama"s Throat.
Most of the time, there is no guard around. But we can"t get out without help. Please rush aid.
MONK.
Carrying the message, Doc strode to an inner room. He had fitted this chamber as a temporary laboratory.
From a bag, he produced a small ultra-violet lantern.
He bathed Monk"s missive with the invisible "black light" beams. On the paper, hitherto unseen lettering sprang out with a weird electric blue glow.
Tip, watching, gasped. She knew what had occurred-from her experience as an espionage agent.
"Invisible chalk," she exclaimed. "A compound which fluoresces when exposed to ultra-violet light!"
"Right," Doc told her. "Each of my men carries a tiny bit of it glued on his scalp, close to the hair roots."
They read the second hidden message: Ignore this note, Doc. The masked guy who is holding us is making me write it. He was going to shoot Renny if I didn"t, so I had to give in. If it had only been Ham, I"d have held out.
MONK.
Did he mean that-about Ham?" Tip asked, somewhat aghast.
"Either one of those fellows would die to save the other one," Doc told her.
Tip sighed. "It takes nerve to wisecrack in a note of that kind. Undoubtedly, they are in deadly peril. It is obvious they are being held alive merely on a chance that their safety can be used to sway you."
"They are being used as live bait," Doc agreed.
Tip eyed him curiously. "What are you going to do about it?"
"Go after them, of course."
"But that"s really what the First Little White Brother expected! It"s a trap!"
Doc nodded. "And I"ve got to go into it."
"Why have you got to?"
"Because the Little White Brother chieftain, if he figures his live bait is no good, will-get rid of it. You know what that means."
Tip shuddered. "They"ll kill your friends.""Can you fly a plane?" Doc asked.
"Yes."
"Good! Go downstairs, or to your room, and wait for me. It may be hours; but wait. I"ll call you."
"But-"
"Scat!" said Doc.
Tip scatted.
EXACTLY six hours later, Doc Savage called pretty Tip Galligan. The bronze man had a touring car in front of the Taberna Frio. It was one of the largest and st.u.r.diest touring cars he had been able to find in Antof.a.gasta.
Monk"s pig, Habeas Corpus, was in the front seat.
In the rear of the car was a huge box, smaller packages, and a powerful motor-generator set. Doc had borrowed the latter from a mine.
Twenty minutes later, they were pulling up beside Doc"s speedy plane. Doc loaded the paraphernalia from the touring car into the plane cabin. For nearly an hour he made painstaking adjustments.
They took off-the pig, Habeas Corpus, grunting beside the motor-generator.
An hour after that, the plane was moaning over the Canyon of the Red Llama. This was a crack in the earth of no mean proportions. Indeed, it had stretches where it rivaled the Grand Canyon of the Colorado. It was just as bare of vegetation as the Grand Canyon, or more so.
At one point, the canyon narrowed to a cramped throat. At this spot, on the crack floor, was situated an abandoned mine. From the air, the tunnel mouth was discernible through binoculars.
Doc Savage studied the tunnel. If some one cared to watch the mine from a distance, there was only one point where this could be done handily-from a rock peak a mile up the canyon.
This peak thrust up like a finger in the middle of the great cut. It bore a tall, spidery tower of steel-a support for a high-tension power line that crossed the Canyon of the Red Llama at this point.
The peak tip was knotty with boulders. A man could hide there-indeed, the rocks were big and profuse enough to conceal a herd of cattle.
Twice, Doc spiraled the big plane over the spot. He saw no one, could see no signs of recent tenancy.
He pointed the moaning nose of the ship upward until he had gathered several thousand feet of alt.i.tude. He touched a lever. Black smoke popped from a delivery pipe aft of the cabin. It strung out behind like a black rope.
The dark smoke became a line which spelled words in the Andean sky.
Tip Galligan, crouched beside the giant of bronze in the plane cabin, held her breath. She had seen skywriting; she was a flyer, hence knew what it took to be skilled at this most difficult aerial art.
She was seeing skywriting executed with an uncanny facility which she would hardly have believed possible.
The great plane seemed to turn into the point of a t.i.tanic, invisible pen. These words were compact, yet so perfectly executed that nowhere did they blur together.
The words read: TO SPRING THAT TRAP WILL MEAN.
YOUR OWN DEATHIt was a very long message, as skywriting goes. Yet it was executed so swiftly that the first letters were still decipherable as the last were finished.
"You"re warning him!" Tip Galligan said wonderingly.
Doc Savage replied nothing. He seldom explained his peculiar code, his set policy of never taking human life with his own hands. Nor did he make a habit of mentioning an interesting fact-that his enemies had a way of coming to untimely ends in traps of their own setting, and that oftentimes Doc had warned them against the very fate which seized them.
Doc flicked another lever on the control panel. This turned the big speed ship over to a mechanical pilot. Doc gestured Tip back in the cabin, and followed her. He started the big motor-generator.
"Here"s how this thing works," he began. With clarity, terseness, he explained what Tip should do.
There was a device not unlike an overgrown searchlight, its innards a maze of wires, bulbs, and screens. It operated on a swivel.
"Keep it pointed at that finger of rock sticking up out of the valley," Doc directed. "The rock spire with the high-line tower atop it-that"s the one!"
THE plane motors quieted like tired animals which had found a place to rest. The ship curled over on a wing tip, went down in a whistling dive; like a rock dropped into a crack, it sank into the throat of the Canyon of the Red Llama.
Doc flattened the bus out half a mile below the mine mouth. The canyon floor was level, smoothed by many cloudbursts. He picked a spot-it was directly in front of the abandoned tunnel-and landed.
"Keep it aimed at the rocky point!" Doc rapped.
Tip nodded. She was holding the weird device in the plane aligned upon the stony peak, using the high-line tower as a bull"s-eye. Behind her, the motor-generator set was shrieking.
Doc ran to the tunnel entrance, and called: "Hey, brothers!"
Out of the black depths came Renny"s great howl. "Doc!"
Monk"s voice echoed: "Beat it, Doc! Didn"t you get my warning in invisible chalk?"
Doc Savage entered the tunnel. His flashlight came out when he was beyond the zone to which sun"s glow penetrated. He soon found his men.
An iron grille, the bars thicker than the wrist of a man, had been erected across the tunnel. The bar ends were bedded deep in pits drilled in the stone. There was a heavy gate in the grille. It was merely barred and padlocked, the padlock in such a position that the men inside could not reach it.
The lock delayed Doc"s skill only a few seconds. A tiny metal probe did the opening work.
The prisoners crowded out. They all but trampled each other in their haste to get to sunlight. Halfway outside, Monk emitted a roar. "Git outa my way, you overdressed shyster!"
Ham said angrily: "I"ll get in your hair if you don"t shut up, you accident of nature!"
Monk, lumbering outdoors, started to retort, but withheld it to stare at the plane.
"Habeas!" he yelled. The pig was peering through the plane window.
Dido Galligan spied his sister.
"Tip!" he cried delightedly, and started forward.
Doc seized him and held him back. "Wait! She"s got a device trained on that hill yonder. Don"t bother her-itmight mean our finish."
Dido gulped. "But I don"t understand what-"
A metallic, ugly voice came from the tunnel behind them.
"You have no chance of taking off in that plane before the canyon walls will be shaken down on you," it said.
"That"s the guy who"s been holdin" us!" thundered big-fisted Renny. He dived for the tunnel.
Twenty seconds later, he came out.
"Holy cow!" he rumbled. "That voice is comin" from a little radio in there!"
"It may be some satisfaction to know that you almost succeeded in thwarting our great purpose," said the voice from the radio. "Savage, you have wiped out all of my aids. Only I alone remain. But I-the First Little White Brother-am sufficient."
Monk opened his mouth. Apparently he intended to yell something.
"Save your breath," Renny advised. "It"s a radio receiving set. There"s no transmitter. You can"t talk back to him."
"But where"s he located?" Monk demanded. "Apparently, he can see us."
"On the rocky finger up yonder, where you see the high-line tower," Doc said. "He must have a portable radio transmitter."
Doc"s five men, Dido Galligan, hawk-faced John Acre-all stared at the rocky spire.
Long Tom chuckled suddenly. "So the light dimming was the right trail, eh? He takes the power for his quake-maker from the high-line. The heavy voltage pull was what caused the lights to dim."
"Right," Doc agreed.