only five of them being men. All the rest were killed, either when the pirates rammed the ships, or here, when they decided the place was becoming crowded." Her face paled at the memory of the horrible massacres, but she went bravely on.

"We have no space-suits, and the pirates, of whom there are perhaps seventy-five, let us wander around pretty much as we please. We know of practically everything that goes on. I happened to hear your name mentioned in the phone room the other day, when a spy on your ship sent a message. When the pirates brought their ship in, crippled by the fight, I was sure that you were around somewhere. I have been watching ever since, making use of a sound detector pieced together from some scraps of material I picked up unnoticed.

"There aren't any guards because the gang is busy repairing the Silver Death, as they call their ship, preparatory to finishing the job they started today. Oh, Jack, you must go, now. They may be through at any time. I don't know when I will see you again, if ever, but I couldn't resist talking to you, touching you, just once more."

"One moment, dear. I have an idea. Is there any compartment, farther back or lower down, where you could gather the prisoners together, and be safe in case the outer wall was broken down?"

"Yes," she replied breathlessly, "one of the older, smaller caves is still airtight, and while the gang is busy on the Silver Death we could go there and close the locks. What good would that do, though? They are certain you can't get in here, or they wouldn't leave the place unguarded. They have your ship surrounded by a wave-proof shield, so you can't communicate with the others of your fleet, you know."

"I know that, but I think I can steal a leaf from their own book. Will they all be working, say three hours from now?"

"I think so. Your guns did a great deal of damage, weakening the forward structures of their craft."

"All right. Get your friends together in the old cave you mentioned, seal it, and then wait till I come back."

Tenderly he kissed her good-bye, then hastened away, anxious to get his work done before the shadow of the cliff again receded.

Thanking the fates for the good fortune that had saved Jean, and had led her to the air-lock at the moment he was there, he stumbled over the rocks and dust piles until halted by the picket line surrounding the San Francisco. He called the men into the ship, and hastened to the pilot room, where Edwards was testing the controls.

"Any luck?"

"Yes, a lot. Can you get the ship in shape to travel in three hours?"

"She's in pretty good shape now, although not capable of the trip back to Earth."

Captain Linet entered at that moment, and with him Professor Erickson.

Holden recounted his adventures of the last hour and then set forth his plan.

"The cave is walled up with thin plating from the ships the pirates have brought in here. The entire gang is at work, repairing their own flier; none of them, or at least only a few, are wearing space suits. I propose to drive the bow of the San Francisco into the wall of their cave, previously weakening it by a few bursts from the hexoxen guns!"

"It is possible," replied Edwards, "but it will probably put us out of commission altogether."

"In any case," put in Erickson, "we will be rid of this damnable shield, and can communicate with our companions."

It certainly was the only plan, for, as soon as the pirates had repaired their ship, another unequal battle would be waged, with the result very little in doubt.

All hands set to work completing repairs on the main stern tubes, the only ones necessary to drive the San Francisco forward. In less than three hours, Edwards pronounced the work done to his satisfaction.

As the light began to creep in toward the base of the cliff, the huge ship rose slightly off the ground, the tubes glowed red and, guided by a powerful searchlight installed on the bow, Edwards pointed his craft toward the gleaming metal patch that marked the position of the pirate cave.

At short range, Holden, Linet, and Erickson opened with the three hexoxen guns. They saw the bursts take effect on the metal. Edwards turned the power on full, and they felt the floor leaping under them. Would the bow of the San Francisco hold? Would they all be crushed to death at the impact? Another moment would tell. Holden saw the metal plates dead ahead, could distinguish the seams marking the air-lock.

He fired one final shot, and flung himself to the floor of the pilot room, endeavoring to find some means of bracing himself for the shock. Then it came! Torn from his position, he saw the plates buckling and heaving about him. The lights went out. A great crash sounded in his ears, and everything went black. In a moment he regained consciousness, and staggered to his feet, bruised and dizzy. Thank God, his space suit had not been harmed! A faint glow from the outside made things visible and he saw that the shock had torn a huge piece out of the plating of the pilot room.

A hand clutched his elbow, and through the phone in his space suit he heard Linet's voice.

"Erickson and Edwards are knocked out. Let's see what we did to these chaps here."

Rushing back through the corridor, they collected as many of the crew as were able to move, flung open the heavy doors of the air-lock, and scrambled down to the floor of the cave.

Here and there lay bodies, pirates caught unawares. Suddenly Holden saw a blue flash. One of the mechanics clutched at his breast and fell, dead in an instant.

"Some of these fellows are still alive. They're using ray pistols," Holden shouted into his suit phone.

Even as he spoke he heard the sound of running feet from the darkness in the rear of the cave, where the bow of the Silver Death was barely visible in her cradle, and in a moment at least fifty figures, pirates who had somehow escaped the fatal cold of space, clad in clumsy suits and brandishing pistols, flung themselves desperately upon the smaller party.

Blue flashes were everywhere as the battle commenced, but the only sound was of struggling feet, with an occasional thud as a body hit the floor. The pirates had been weakened by their long stay on the moon, and moved slowly, but the surprise of their attack, and the superiority of numbers had given them some advantage. It was man to man fighting, savage and merciless.

Holden, with a neat dive, knocked the feet from under a huge fellow who had trained a pistol on him, and they rolled over and over, each trying desperately to gain a second's advantage. He heard a dull crash to one side, as Captain Linet, jumping high into the air, landed with stunning force on a bewildered assailant. Thinking of Jean, waiting for him in some dim corner of the cave, he redoubled his efforts.

For a fraction of a second his pistol pointed toward his antagonist's body, and that was enough. He pressed the release, and the deadly ray shot into the body beneath him, dealing instant death. Freeing himself from the cold grip, he ducked an empty pistol flung at him by a new assailant. Again his finger bent, and another body dropped to join those lying motionless on the floor.

A fast-moving shadow caught his eye. He saw one of the pirates detach himself from a writhing group and head for the side of the cave. That was the place where Jean had said she would be waiting!

Pausing only an instant to make sure that his pistol was still charged, Holden sprang in pursuit of the fleeing form. He saw him stoop and pick up a heavy bar from the floor. The coward was going to burst open the chamber where the helpless captives waited! It was impossible to aim at that speed, so Holden forced his flying feet to move still faster, and foot by foot he drew closer to the man he pursued. Metal plates again gleamed in front of him, and he saw the pirate raise the bar high over his head,