"They're mad and we aren't, yet," said the boy. Then, seeing that he hadn't made himself clear, "In a fight, if a guy gets mad he starts swinging wild and then you nail him." Smiles splintered the ice of tension. Captain Llud said, "Maybe you've got something there. They seem to be mad, all right. But we're not in a position to throw any punches." He turned back to the others. "As I was going to say--I think we'd better try to parley with the enemy. At least we may find out who he is and why he's determined to smash us." And now instead of tight-beam detectors the ship was broadcasting on an audio carrier wave that shifted through a wide range of frequencies, repeating on each the same brief recorded message: "Who are you? What do you want? We are the interstellar expedition _Quest III_...." And so on, identifying themselves and protesting that they were unarmed and peaceful, that there must be some mistake, and querying again, "Who are _you_?" There was no answer. The ship drove on, its fuel trickling away under multiplied demands. Those outside were squandering vastly greater amounts of energy in the effort to batter down its defenses, but converting that energy into harmless gravitic impulses was costing the _Quest III_ too. Once more Knof Llud had the insidious sense of his own nerves and muscles and will weakening along with the power-sinews of his ship. Zost Relyul approached him apologetically. "If you have time, Captain--I've got some data on Earth now." Eagerly Llud took the sheaf of photographs made with the telescope. But they told him nothing; only the continental outlines were clear, and those were as they had been nine hundred years ago.... He looked up inquiringly at Zost Relyul. "There are some strange features," said the astronomer carefully. "First of all--there are no lights on the night side. And on the daylight face, our highest magnification should already reveal traces of cities, canals, and the like--but it does not. "The prevailing color of the land masses, you see, is the normal green vegetation. But the diffraction spectrum is queer. It indicates reflecting surfaces less than one-tenth millimeter wide--so the vegetation there can't be trees or grass, but must be more like a fine moss or even a coarse mold." "Is that all?" demanded Llud. "Isn't it enough?" said Zost Relyul blankly. "Well--we tried photography by invisible light, of course. The infra-red shows nothing and likewise the ultraviolet up to the point where the atmosphere is opaque to it." The captain sighed wearily. "Good work," he said. "Keep it up; perhaps you can answer some of these riddles before--" "_We know who you are_," interrupted a harshly crackling voice with a strange accent, "_and pleading will do you no good._" * * * * *