"The sound of whales..."
Lin Mo stared at the pulsating sonogram on the console, Chen Rui’s dying words echoing like a ghost in his mind. The research submarine *Deep Sea Explorer* was cruising three hundred meters beneath the Pacific Ocean, its cabin bathed in the eerie blue glow of instrument lights that carved his profile into alternating fragments of light and shadow.
"The acoustic frequency has changed again," Su Yuqing’s voice came through his headset, accompanied by the chaotic background noise of the shore-based control center. "This time it's 17.8 Hertz, 0.3 higher than last time."
Chapter 211