"The Watch planes we sent to join you," said a curt voice he recognized as that of the Commanding General of the United Nations, "have located an invisible barrier by their sonic altimeters. Four of them seem to have rammed it and exploded without destroying it. What have you to report?" "I've seen the flashes, sir," said Thorn unsteadily, "but they made no noise. And there's no wind, sir. Not a breath since the blue flash I reported." A pause. "Your statement bears out their report," said the G.C. speaker harshly. "The barrier seems to be hemispherical. No such barrier is known on Earth. These must be Martians, as the Com-Pubs said. You will wait until morning and try to make peaceful contact with them. This barrier may be merely a precaution on their part. You will try to convince them that we wish to be friendly." "I don't believe they're Martians, sir--" Sylva came racing to the door of the plane. "Thorn! Something's coming! I hear it droning!" Thorn himself heard a dull droning noise in the air, coming toward him. "Occupants of the rocket-ship, sir," he said grimly, "seem to be approaching. Orders?" "Evacuate the ship," snapped the G.C. phone. "Let them examine it. They will understand how we communicate and prepare to receive and exchange messages. If they seem friendly, make contact at once." * * * * * Thorn made swift certain movements and dived for the door. He seized Sylva and fled for the darkness below the plane. He was taking a desperate risk of falling down the mountain-slopes. The droning drew near. It passed directly overhead. Then there was a flash and a deafening report. A beam of light appeared aloft. It searched for and found Thorn's plane, now a wreck. Flash after flash and explosion after explosion followed.... They stopped. Their echoes rolled and reverberated among the hills. There was a hollow, tremendous intensification of the echoes aloft as if a dome of some solid substance had reflected back the sound. Slowly the rollings died away. Then a voice boomed through a speaker overhead, and despite his suspicions Thorn felt a queer surprise. It was a human voice, a man's voice, full of a horrible amusement. "Thorn Hardt! Thorn Hardt! Where are you?" Thorn did not move or reply. "If I haff not killed you, you hear me," the voice chuckled. "Come to see me, Thorn Hardt. Der dome of force iss big, yes, but you can no more get out than your friends can get in. And now I haff destroyed your phones so you can no longer chat with them. Come and see me, Thorn Hardt, so I will not be bored. We will discuss der Com-Pubs. And bring der lady friend. You may play der chaperon!" The voice laughed. It was not pleasant laughter. And the humming drone in the air rose and dwindled. It moved away from the mountain-top. It lessened and lessened until it was inaudible. Then there was dead silence again.