THE bronze man got Hannah positioned on his back as he wished. Then, as a matter of precaution, he used the long, silken line which was attached to the collapsible climbing grapple which he always carried, and took a few turns around them, so that the girl would not fall off."This is crazy business," Hannah whispered. "Say, wait a minute! Oh, great grief! You're not going to swing from tree to-"

Doc took off. He made a long run out into s.p.a.ce on a swaying, bending bough, as if it were a springboard, and went out into s.p.a.ce.

Hannah didn't scream. She was too scared. Then the bronze man caught a bough of the next tree, flipped up and on through dizzy nothingness.

Hannah shrieked then. And immediately the jungle was thundering with rifle noise. Bullets cut through the foliage, aimed blindly at the sound. They were probably not as close as they sounded.

Doc landed on a sloping tree trunk, ran up with hands and feet, got into the dizzy heights, stepped to another limb, which bent alarmingly, dropped from that to another, ran along it, was in s.p.a.ce again.

Hannah shut her eyes. She did not make any more sound.

Doc traveled through the jungle lanes for a quarter of an hour, judged they were safe, and stopped.

He untied Hannah. She immediately wrapped both arms and legs around a tree bough. For a while, she was without words.

"Why can't a person faint when she wants to?" she gasped finally.

Doc examined bruises which her fingers had made as she clung to him during the aerial voyage.

"The silk cord was probably excess caution," he said. "You wouldn't have fallen off."

"Don't you ever," said Hannah grimly, "do a thing like that again without first telling me about it."

"You would have refused," Doc said.

"You bet I would have," she agreed heartily. "I wish I could have. I wouldn't have done that for anything.

That was the worst thing that ever happened to me."

Doc was silent.

Hannah said, "That was the first time I was ever so scared that I screamed. I'm sorry about that. But I couldn't help it."

Doc smiled slightly. She had not been nearly as frightened as he had expected. Once he had done something similar with Ham Brooks, who was not supposed to have any nerves, and Ham had fainted.

Hannah sighed. She climbed down with infinite care until she was on the ground. She stamped the ground as if to make sure it was real and enjoy its solidness.

"What," she asked, "do we do now?"

"Try to find the answer to this mystery," Doc explained, "and go on from there."

THE afternoon was well along now. In an hour or two, it would be dark.

Doc and Hannah had climbed the sharp face of the volcanic cone to a height of a few hundred feet, not so high as to be out of the jungle protection, but high enough to get a point for general observation.Below them was a considerable flat area, not very wide, not much more than a quarter of a mile at any point, but a flat land that was long, the full length of the island on that side.

"There," said Hannah, "is where the American government was to build its airfield runway."

The location was good, Doc could see. A few big bulldozers could strip the jungle and level the ground in a short time, to make the runway. It was long enough for heavy bombers. And the direction was right, into the prevailing trade winds. Since, the wind always came from one direction, more than one runway would not be necessary.

(The prevalence of strong winds from one direction is characteristic of many of the Caribbean islands. On some islands, of which the island of Curacao is typical, the steady, hard winds have pulled trees out of shape, all branches growing off in one direction with the wind, instead of in all direction as in a normal tree.) While they were studying the lay of the ground, noise of a plane came out of the distance. It was a moderately large ship, civilian.

"The seaplane," said Hannah. "The one which picked up the parachutists and"-she glanced at Doc-"flew off toward my island, Geography Cay."

The plane did not land immediately. It flew a leg off to the south, then to the north, then into the east.

"Reconnoitering," Doc said.

"But why?"

They learned the reason for the reconnoitering after the seaplane came back and landed, taxied up to the beach, and the crew got out.

They watched closely, saw one prisoner taken from the plane.

"Major Lowell," Hannah said. "At least, they still have him alive."

Major Lowell was dragged into the largest of the stone buildings, the same house into which the other prisoners had been taken. There were armed guards at the door, and other guards patrolling here and there.

"Notice the military manner of those guards?" Doc asked.

Hannah frowned at the scene. "You know, they do act like soldiers, at that. But they are in civilian clothes."

Doc said, "Watch that man moving from one guard to another. He seems to be a noncommissioned officer, checking up on the guard. Watch them salute him."

Hannah observed one of the patrols click off a salute. She gasped.

"That's not an American salute!" she exclaimed. She looked at Doc. Her face got pale. "That was . . .

was an enemy salute!"

THEY were ready, then, for the submarine.The craft got a signal first. A man walked to the beach edge with three fused sticks of dynamite. He lighted the fuses from a cigar, threw the sticks far out into the water. The dynamite exploded at intervals of three or four seconds. The impact doubtless was carried out underwater to the submarine.

The sub surfaced a few moments later. She had been waiting for the signal.

Hannah exclaimed, "The seaplane! It scouted the adjacent sea to make sure everything was clear!"

"It is an enemy submarine, all right," Doc said. He studied the submersible with interest. "Cargo," he said.

Hannah was pointing at the spot where the underseas boat had surfaced.

"Black bottom," she said. "I remember, out there where it was lying. There is a lot of seaweed over black sand. There are several spots around this island, and around all these islands. A submarine lying there could not be seen regardless of how bright the sun was or how close over the spot a reconnaissance plane flew."

Doc still had a tiny gadget which he habitually carried, a tube with an arrangement of lenses so that it could be used as telescope, periscope, breathing tube for use under water, and other purposes. He got it out and examined the submarine.

"Cargo, all right," he said.

Hannah stared. "Cargo," she said. "You mean that's not a combat submarine?"

"They probably have torpedo tubes and you can see two deck guns," Doc said. "But this ship is large, and built for underwater travel over great distances at high speed. A few of them have been sunk, and it is believed they have been more than mother ships for smaller combat submarines."

The submarine moved insh.o.r.e. It came rapidly, for the water was deep and free. Close to the beach, it slackened speed. When it grounded, the bow of the submersible was not more than ten feet from the beach sand.

They began rigging the equivalent of a breeches buoy, a kind of continuous conveyor for cargo.

Hannah was impressed by the efficiency.

"They've done this before," she said.

SAILORS were scrambling off the submarine. It was evident that everyone was getting a short leave ash.o.r.e to stretch his legs.

Some of the submarine crew bolted for the house, where there was evidently food and liquor. Others wandered over to the wire pen, examined the native prisoners, and shouted ribald jokes at the colored women inside.

Meantime, a squad had been formed of the men who already had been on the island. These began escorting prisoners aboard the submarine.

First prisoners taken aboard were Monk and Ham. Renny and Johnny were next. Then Major Lowell and Stony Smith. Two men ran down the beach chasing the two pets, Habeas Corpus and Chemistry.

They did not catch the animals.Now they began removing the natives from the compound and placing them aboard the submarine.

"Why are they taking those people away on the submarine?" Hannah pondered aloud.

"The reason," Doc said, "should be fairly obvious."

She frowned. "You mean, they're going to take them to Europe as war prisoners to get them away from the island?"

"Those natives in the compound," Doc said, "are the descendants of pirates, you say?"

"Yes." Hannah nodded. "They are about like the people on my island."

"Would they," Doc asked, "stand by and see something done that would help the Axis powers?"

Hannah shook her head instantly. "They would not. They have their own rather strange customs, and their code of conduct is not the code of many people, but they wouldn't do that. In fact, I happen to know that many of them have tried to get into the English or American navy."

"Then," Doc said, "if the natives here found out the Axis was using the island, they would not stand for it?"

Hannah's face was grim.

"So that's why they're prisoners," she said. "But I don't understand why that submarine is in here. What is going on? They are not using the island as a submarine base. They could not get away with that.

American patrol planes fly over the island regularly, looking for just that sort of thing."

"You remember the parrot's nest?"

"Remember it!" she exclaimed. "The thing has me silly. It doesn't make sense."

"We will probably find," Doc said, "that it wasn't exactly a parrot and its nest that was so important. But that the parrot and the nest was responsible for the trouble starting."

She shook her head. "I do not understand."

Doc indicated the volcanic cone behind them. "The formation of this island is unusual."

"Lots of these islands are volcanic in origin-"

"This one is different. At first, it appears to have been formed by an upheaval, then by lava which built up the top of the cone and spilled down the sides in places. That is not in itself extraordinary. But the geological formation is not usual."

"You mean, there's a connection?"

"Apparently."

"If you've made a guess," she said, "I wish you'd tell me what it is."

DOC SAVAGE seemed not to hear the request. He watched the beached submarine for a while. The bow of the craft was resting on the beach, but they could float it again by blowing some of the ballast tanks.Prisoners were still being marched aboard. It was evident that they intended to put all the natives on the vessel. The natives were not going aboard willingly, but so far it had not been necessary to shoot anyone.

Doc turned to Hannah. "Your wrist watch running?"

She examined the timepiece, compared it with Doc's watch. "Seems to be all right. Only about two minute difference in time."

Doc set the watches to the same time.

"In exactly one hour," he said, "I want you to walk down to the beach and join them."

Hannah stared at him blankly.

Doc said, "Tell them you have decided to join them, and that you want fifty thousand dollars."

"I wouldn't join them for fifty million," Hannah said.

Doc was silent for a while. "Does that mean you will not tell them that?"

"Of course not," she said. "I'll tell them anything you say-if it will help corner them."

Doc nodded.

"Convince them," Doc said, "that your information is valuable. Tell them that it has to do with something I did."

Hannah said, "All right. What did you do?"

Doc took a small grenade out of his clothing. "This is a time bomb," he said. "Now, I am going to leave you here. I have a job to do with the bomb. That submarine is not going to reach Europe."

Hannah smiled thinly. "That is what I am to tell them?"