Translator: Nyoi-Bo Studio Editor: Nyoi-Bo Studio

  Some year, some month, some day. Some sea area. 200 meters below sea level. Twilight zone.

  In that depth underwater, the sun was as dark as dusk.

  Looking down, there was a dark abyss. Looking up, the top was like just after sunset: that short moment of blue sky right before the sky completely darkened.

  What was really different from the real sky was that there were no tired birds returning to the forest, and occasionally there would be a streamline shadow swimming at a high speed overhead––a large shark in shallow water.

  The depth was beyond the reach of at least half of the marine life, but in the faint light, there were still some things quietly moving.

  Hu—


  A shadow swam at a very high speed. Its body reflected a dim, silver light. Very few things could swim at this kind of speed in the sea.

  It was a nearly two-meter-long, adult swordfish. Its long jaw was shaped like a fencing sword, and it wandered wildly through the sea without restraint. In the deep ocean, it had few natural enemies, besides sharks, due to its excellent speed.

  Its eyes were very big, as big as tennis balls, scattered with a large number of photoreceptors. It would be impossible for it to hunt in such light without some special features on its body.

  It had sharp jaws, keen vision, and hundreds of kilograms of body weight. It had a short distance speed of more than 100 kilometers per hour, and had gained the capital to be prideful. When it went crazy, it was as scary as a harpoon, and had even earned the title of, “Piercing Through Wood Every Day”


  The swordfish was not very lucky that day, however, as it had not found anything to eat. Hunger turning it into a grumpy old man. It really wanted to find something to smash––anything would be all right.

  At the front of its high-speed swimming route, a big, black fellow suddenly appeared. With a slow swimming speed, the swordfish was 70 to 80 percent sure that it was a whale.

  Even if it was a whale with the fastest speed, it was still not even able to eat the tailwind of the swordfish. The swordfish had a lot of confidence as it went to provoke it.

  Its speed was too fast––so fast that the other party had not even seen what was happening before it rushed over. Only when the swordfish got closer did it realize there was something wrong. It hurriedly twisted its strong muscles to make a sharp turn, just managing to prevent colliding with the other party.

  What was going on? Why was this fellow’s body so long? It was much longer than the biggest whale it had seen before… It had a perfectly round head; its “dorsal fin” was as thick as a reef rock; its pectoral fin was so small that it could hardly be seen; and its tail fin rotated periodically to stir the sea water. No matter how one looked at it, it did not seem like a dumb whale… Most importantly, the other one’s skin seemed a lot harder to smash than a wooden plank.

  Forget it, it was better to find some push-over to pinch.

  With a flick of its tail, it angrily swam away and disappeared in the dim light.

  The nuclear submarine, that had been mistaken for a whale by the swordfish, cruised silently underwater at a speed of six knots. Along the way, it traveled under dozens of different types of ships, including fishing boats, cargo ships, oil tankers, private yachts, and it even took the risk to venture close to the warships. Fortunately, it had not been noticed by any ship.

  Behind it, it towed a long long “tail,” longer than any tail in the natural world, and its total length was around one kilometer. It had an 800 meters long, less than one centimeter thick, towline and a more than 100 meters long sonar array composed of more than a thousand hydrophones.

  The towed sonar array operated at wavelengths below 3000 Hertz, with very low frequencies varying between ten to twenty Hertz in the lowest frequency range. Through deep-sea channels and convergence zone effects, the longest detection distance reached 180 kilometers, and information and topographical features could even be obtained outside of the territorial sea boundary of other countries.

  ******

  In the narrow sonar room.

  The Sonar Team Member One, who was wearing a military uniform and headphones, was focused on the monitor in front of him, looking for traces of enemy nuclear submarines.

  All sounds within the range of 180 kilometers were captured by the sonar arrays, transmitted to Sonar Team Member One’s headphones after they were amplified. The waveform was displayed on the screen in front of him using a tuning indicator.

  The Sonar Team Member Two sitting at his side was in charge of the operation of the sonar at the bow of the ship and the echo sounder.

  Sonar Team Member One periodically switched between buttons and adjusted the filters, sometimes decreasing to a low frequency and sometimes increasing to a high frequency, in order to prevent enemy submarines from approaching quietly in the shadowy areas.

  The sparse stubble on his lips proved that he was very young, but he had been on duty in the submarine for a year. He was not a new recruit who panicked when things happened, as could be seen from his calm and experienced expression.

  He knew most of the different sounds that alternately sounded in the headphones very well. If it was not for that, he would not have the qualifications to enter the submarine; he was essentially the eyes and ears of the submarine.

  The nuclear submarine was very quiet. The noise coming from it was very small, and it was far less noisy than diesel submarines.

  He could distinguish and identify the crisp crackling sounds of the shrimp, the sharp chirping of dolphins, the unpleasant cricket sound from the Golden Drum Fish… His incredible and keen observation skills were something that a normal person would not be able to imagine, but to him, it was just a part of his work and training. He did not have any extraordinary hearing power, it was just that after hearing the same sounds many times, he remembered them. It was nothing else, just that he had become familiar.

  Suddenly, his straight eyebrows moved slightly. He heard an unfamiliar sound in his ears, which stopped almost as soon as it began.

  He did not let go of any anomalies. The waveform on the screen still remained in his memory, and based on his intuition, he adjusted the button, opening the low pass filter, and decreasing the frequency.

  The sound returned again. His eyeballs turned rapidly, and he took a slight glance at the frequency; it was between 45 to 50 Hertz.

  Was it a whale?

  The submarine often met whales, and he knew all kinds of whales’ sounds very well. In his memory, there were indeed some whales that could make sounds in that frequency range, but the specific sounds of their calls were different from what he had heard just then.

  “Number Two, please confirm the position. The frequency range is 45 to 50,” he said.

  As the towed sonar was a straight line, it was very hard to confirm whether the sound came from the port or the starboard. It needed the assistance of other sonars, or the maneuvering of the submarine, to confirm where the sound came from, but the submarine in its cruising state could not change direction just because of a little abnormality. Only the former could be chosen.

  “Understood,” Sonar Team Member Two answered crisply. He adjusted the sonar at the bow of the boat to the same low-frequency gain of 45 to 50 Hertz.

  Sonar Team Member Two, who was young as well, stared and listened for a while before saying, “Bearing is 090, identity unknown.”


  “Received!” Sonar Team Member One said.

  “Sir!” He took off his headphones and called the officer-on-duty.

  “What’s wrong?” The officer-on-duty immediately walked over. He was much older than Sonar Team Member One and was really mature and sophisticated. The wrinkles in the corners of his eyes and the military rank on his shoulders also proved that point.

  “Suspicious contact, bearing is 090. The sound seems like a whale,” Sonar Team Member One reported concisely.