Four men picked up the herculean frame of the unconscious doctor and hoisted him up on the table. Carson seized his head and bent it forward and the dwarf took from a case a syringe with a five-inch needle. He touched the point of it to the base of the doctor's brain. "Slavatsky! Look!" cried Frink. With an exclamation of impatience the dwarf turned and stared at a disc set on the wall of the cave. It was glowing brightly. With an oath he dropped the syringe and snapped a switch, plunging the cave into darkness. A tiny panel in the door opened to his touch and he stared out into the light. "Soldiers!" he gasped. "Quick, the back way!" As he spoke there came a sound as of a heavy body falling at the back of the cave. Slavatsky turned the switch and flooded the cave with light. At the back of the cave stood Operative Carnes, an automatic pistol in his hand. "Open the main door!" Carnes snapped. * * * * * Slavatsky made a move toward the light, and Carnes' gun roared deafeningly in the confined space. The heavy bullet smashed into the wall an inch from the dwarf's hand and he started back. "Open the main door!" ordered Carnes again. The men stared at one another for a moment and the dwarf's eyes fell. "Open the door, Frink," he said. Frink moved over to a lever. He glanced at Slavatsky and a momentary gleam of intelligence passed between them. Frink raised his hand toward the lever and Carnes gun roared again and Frink's arm fell limp from a smashed shoulder. "Slavatsky," said Carnes sternly, "come here!" Slowly the dwarf approached. "Turn around!" said Carnes. He turned and felt the cold muzzle of Carnes' gun against the back of his neck. "Now tell one of your men to open the door," said the detective. "If he promptly obeys your order, you are safe. If he doesn't, you die." Slavatsky hesitated for a moment, but the cold muzzle of the automatic bored into the back of his neck and when he spoke it was in a quavering whine. "Open the door, Carson," he whimpered. There was moment of pause. "If that door isn't open by the time I count three," said Carnes, "--as far as Slavatsky is concerned, it's just too bad. I'll have four shots left--and I'm a dead shot at this range. One! Two!" His lips framed the word "three" and his fingers were tightening on the trigger when Carson jumped forward with an oath. He pulled a lever on the wall and the door swung open. Carnes shouted and through the opened door came a half dozen marines followed by an officer. "Tie these men up!" snapped Carnes. * * * * * In a trice the six men were securely bound and Frink's bleeding shoulder was being skilfully treated by two of the marines. Carnes turned his attention to the unconscious doctor.