"Now we've put our foot in it, clear to the knee!" Costigan exclaimed, as he shot the lifeboat upward at its maximum power. "Look at that! I knew that Nerado could trace us, but I didn't have any idea that _they_ could. It's a good thing these ultra-vision plates don't need light to see by or we'd be _'spurlos versenkt'_ in a hurry!" Staring with Costigan into the plate, Bradley and the girl saw, not the Nevian sky-rover they had expected, but a fast submarine cruiser, manned by the frightful fishes of the greater deeps. It was coming directly toward the lifeboat, and even as Costigan hurled the little vessel off at an angle and then upward into the air one of the deadly offensive rods, tipped with its glowing ball of pure destruction, flashed through the spot where they would have been had they held their former course. But powerful as were the propellant forces and fiercely though Costigan applied them, the denizens of the deep clamped a tractor ray upon the flying vessel before it had gained a mile of altitude. Costigan aligned his every driving projector as his vessel came to an abrupt halt in the invisible grip of the beam, then experimented with various dials. "There ought to be some way of cutting that beam," he pondered audibly, "but I don't know enough about their system to do it, and I'm afraid to monkey around with things too much, because I might accidentally release the screens we've already got out, and they're stopping altogether too much stuff for us to do without them right now." He frowned as he studied the flaring defensive screens, now radiating an incandescent violet under the concentration of the forces being hurled against them by the warlike fishes, then stiffened suddenly. "I thought so--they _can_ shoot 'em!" he exclaimed, throwing the lifeboat into a furious corkscrew turn, and the very air blazed into flaming splendor as a dazzlingly scintillating ball of energy sped past them and high into the air beyond.