In a second, his whole plan, which had seemed to be approaching success so rapidly, was smashed by the disappearance of the submarine. Mechanically he kept his helmet-light playing into the ever-thickening eyes and tentacles around him, while he scanned the sea-floor nearby. It was filling more closely than ever with the black, writhing forms of the cuttlefish. The rays still held them back, but their great bulk loomed over the small party of humans like a sinister storm cloud. Soon, in their overwhelming mass, they would crush down, and the submarine's crew be conquered by sheer force of numbers. "Look!" Keith cried. "There's where she was lying!" He pointed out on the floor of the square a deep groove, obviously made by the hull of the _NX-1_. Its length and jaggedness seemed to denote that the submarine had tried to bore into the bed of the cavern itself. Wells was mystified. If the octopi-ship had towed her away, she would certainly not have gouged that deep scar on the sea bottom.... But he dismissed the strange disappearance from his mind. He had to work out a plan of action. "Keep together, men, and follow that scar!" he ordered tersely. "There's a chance that the _NX-1's_ somewhere further along!" It was a futile hope, he knew--but there was nothing else. The tiny group, centered in the inverted bowl of black, writhing tentacles, lumbered onward. * * * * * Then the octopi struck with another weapon, in an effort to dull the spearing beams of white. Here and there from the mass of black an even blacker cloud began to emerge. It quickly settled over the whole scene, pervading it with a pitchy, clinging darkness that obscured each man from his neighbor. "Ink!" cried one of them. It was sepia from the cuttlefish's ink sacs--the weapon with which these monsters of the underseas blind and confuse their victims. "Faster!" the commander roared in answer. "And for heaven's sake, keep together!" They huddled closer. Under the protecting cloud of ink the mass of octopi pressed nearer. The struggle became fantastic, unreal, as the brilliant beams of white bored through the utter blackness searching for eyes which the men knew were there, yet could not see until their rays chanced upon them. Snaky shadows milled horribly close to the little group of bulging yellow figures. Blacker and blacker grew the water; they could not always see the monsters as they drove them back on each side. Now and then a bold tentacle actually touched one of them for a moment before its owner was thrust, blinded, away.