Turning the wireless up to its full capacity, Onodera at tempted contact with the Tatsumi Maru. At length Yuki’s voice came through. The reception was terribly weak and marred by static.
“What is it?” came the faint response. “We lost all trace of you just now. We had been monitoring your sonar vibrations.”
“We ran into some strange-looking ruts at the bottom of the trench,” said Onodera. “So what we’re going to do now is follow them, going east. Take a verification of my position.”
“All right,” answered Yuki. “In one minute give me a signal. And then let’s have a sound wave every minute after that.”
His eye on his stopwatch, Onodera let a minute elapse and then sent up a signal from the ultrasonic oscillator. When he had gotten a reply verifying his position, Onodera set the oscillator at one-minute intervals and started the submarine forward. He steered it into a shallow curve, and, passing over two ruts, he lined up the vessel’s axis with the third and then moved forward at a speed of three knots. Apparently they had not yet reached the deepest part of the sea trench. In front of them there was a gentle grade of about twenty degrees, which fell off to the east. The vessel moved ahead, its guide chain maintaining a fixed distance from the sea floor. The water pressure began to climb slightly. After they had gone a mile and a half, the rut broadened, almost doubling in width, and it also grew shallower. Finally it disappeared into the ooze. All was silent save for the faint ping of the oscillator and the quiet vibration of the motor.
“We’re down to 23,950,” said Onodera. “The slope of the floor is getting steep all of a sudden.”
“The water’s gotten muddy,” said Tadokoro.
Suddenly the nose of the vessel rose up with a thumping noise. It climbed some sixty feet above the sea floor before Onodera could check it.
“Are we all right?” asked Yukinaga, gripping his chair as the submarine pitched forward and back. The dim cabin light showed his forehead beaded with sweat.
Without answering, Onodera gripped the control stick and brought the vessel some ninety feet farther up. The pitching lessened at once. How incredible, thought Onodera, a current so violent that close to the floor of a trench! He leveled out on a course 180 feet from the bottom. The vibrations ceased almost entirely.
“Should we go down again?” Onodera asked.
“No ...” muttered Tadokoro as though uncertain.
“How about a flare?”
“Give it a try.”
Onodera opened the lid of a small control box to his right and depressed one of the six levers it contained. There was a faint shock. Then in the upper portion of the television screen a dazzling sphere of brilliance burst into view. Surrounded by a frenzied mass of bubbles, it slanted slowly downward.
The two scientists, clinging to the edge of the observation window, gasped with surprise. Onodera fixed his eyes on the television screen. What had come into view, lit by the blue-white glare of that underwater sun, was peak upon peak of gray-yellow clouds of mud, wavering in the current and stretching far into the distance like a vast sea of stratocumuli seen from an airplane.
“Can we go down?” muttered Tadokoro.
“We can try 150 feet,” said Onodera.
“All right. Be careful ...” said Tadokoro. “Make sure that we can go back up at any moment.”
Onodera released a spurt of gasoline from the small tank used to trim the vessel, and the Wadatsumi began to sink rapidly. Startled, Onodera let go some ballast and lessened the rate of descent. They were already in the midst of the muddy clouds, however. Once more the vessel began to tremble violently. Gradually Onodera brought it up forty-five feet, climbing out of the clouds. Another blow struck the Wadatsumi, and it began to rock from side to side.
“Let’s try another flare,” said Tadokoro, absorbed in the instruments and oblivious to the new crisis.
As he fired the flare, however, Onodera, reacting to some instinct of danger, released a large quantity of ballast, and the whirlpool of brown cloud beneath them suddenly fell away. An instant later a fierce rush of water hit the Wadatsumi broadside, tipping it over and sweeping it far off course before Onodera could reassert control and start the engine. The submarine then began to rise steadily.
“Professor Tadokoro! Look there!” Yukinaga cried.
The flare that had been released before the current struck them was drifting in the distance, shedding its light upon the yellow-brown chaos below. At the extreme edge of the light, some huge thing was churning with terrible force—a mass of mud cloud tinged with green. Swelling as it came, it was pouring down the sloping side of the trench, down out of the darkness above.
“A turbulent mud current!” shouted Tadokoro, his voice uncharacteristically shrill. “We’re the first ones to actually lay eyes on one.”
“But . . . at this depth?” asked Yukinaga, trembling with excitement. “It looks as though it’s pouring out of the side of the trench.”
“I’m going to take us all the way up,” said Onodera, regaining his voice. “There was a message from the ship. The surface is getting rough.”
The Wadatsumi began its lonely ascent at a point some 240 feet above the rolling sea of mud which filled the trench. Like a balloon cut loose from its moorings, it soared upward with steadily increasing speed toward the silver sky that glinted nearly 24,000 feet above it. Onodera fired off the three remaining flares. They burst and hung suspended above the Wadatsumi, their burning blue-white glare creating a circle of light more than a mile in diameter.
For the first time Onodera was able to grasp something of the total environment that enclosed them—that vast, crushing environment of chill, clear water. Far off to the left, at the very edge of the light, loomed the dark face of the trench wall, merging into the blackness beyond. The twisting yellow-brown mud current was now far below them, but Onodera could make out the faint shadow of the Wadatsumi falling upon it, a tiny metal cylinder suspended in a void.
The Japan Trench. That deepest of trenches, whose broad expanse lay nearly 24,000 feet below the sunlit waves of the vast Pacific. Now in that immense watery void, something was stir ring. That icy, monstrous serpent of blackness that lay within the trench, stretching from one end of it to another—it was beginning to writhe beneath the terrible weight of pressure piled upon it. It was beginning to edge its body forward.