"He's sinking--whatever he is," Keith muttered to Hemmy. "Hey, Sparks! Get me Captain Knapp." A moment later the connection was put through. "Bob? This is Wells again. Bob, our location chart shows the presence of some strange undersea metallic body. It can't be a submarine, for my maritime reports would show its presence. We think it has some connection with the 'machine-fish' that survivor raved about. At any rate, I'm going after it. The world has a right to know what destroyed that fishing fleet, and since the _NX-1_ is right on the spot it's my duty to track it down. Re-broadcast this news to land stations, will you? I'll keep in touch with you." Knapp's voice came soberly back. "I guess you're right, Keith; it's up to you.... So long, old man. Good luck!" * * * * * In Wells' veins throbbed the lust for action. With control studs at hand, location chart and teleview screen before his eyes and fifteen men waiting below for his commands, he had no fear of any monster the underseas might spew up. He glanced swiftly at the location chart and depth indicator again. The mysterious red spot was slowly coming across the _NX-1's_ bows at a distance of about one mile. Keith punched a stud, and, as his craft filled her tank and slipped down further into deep water, he spoke to Hemmy Bowman. "Take control for a minute. Keep on all speed, and follow 'em like a bloodhound. I'm going below." He strode down the connecting ramp to the lower deck, where he found fifteen men standing vigilantly at posts. At once Keith plunged into a full explanation of what he had learned up in the control room. He concluded: "A great moral burden rests on us--every one of us--as we will soon come face to face with a possible world menace. Anything may happen. A state of war exists on this submarine. You will be prepared for any wartime eventuality!" Sobered faces greeted this announcement, and perceptibly the men straightened and held themselves more alertly. Wells at once returned to the control room. A glance at the location chart and its two tiny lights told him that the intervening distance had been decreased to about half a mile. The depth dial showed them both to be two miles below, and steadily diving lower. Charts showed the sea-floor to be three miles deep in this position, and that meant-- "Look there!" exclaimed the first officer suddenly. "It's changing course!" * * * * * The crimson stud had suddenly shifted its course, and now was fleeing directly before them. For a moment the distance between the green and red lights remained constant--and then Keith Wells stared unbelievingly at the chart, wiped a hand across his eyes and stared again. "Why--why, the devils are as fast as we!" he exclaimed in amazement. "I think they're even gaining on us!" "And there's no other submarine in the world that can do more than thirty under water!" Hemmy Bowman added. "We're hitting a full forty-one!"