Pier Four, Invercargill.

  Once a hub where thousands of tons of cargo passed through each day, the dock had become a jagged graveyard of shattered concrete and rusted containers. The seawater was poisoned—thick, iridescent oil slicks drifted across its surface like dead snakes. Above them, the silver fragments in orbit scattered reflected light, painting the harbor in a warped, unnatural glow.

  Ethan hid the truck deep inside an abandoned warehouse and led Mei onward through the salt-crusted ruins. At the farthest edge of the dock, half-submerged beneath layers of thick algae and calcified shellfish, lay a massive, prehistoric steel shape.

  “This is it?” Mei stared, her hand tightening on her rifle. “Our way out?”

  What stood before her looked less like a submarine and more like the rotting carcass of a steel whale.

  “Nautilus Twenty-One,” Ethan said calmly. “A diesel-electric submarine. Decommissioned sixty years ago.”

  He released the hatch locks with practiced, heavy movements. CLANG— The steel door groaned open, spilling out air thick with the smell of wet mold and ancient oil.

  “You’re insane,” Mei snapped, stepping back. “In this world? The Alliance’s Blue Shark subs hit eighty knots underwater. This thing looks like it would struggle to make ten.”

  “Exactly,” Ethan replied, his voice echoing from the dark interior. “The Blue Sharks are children of the digital age. No satellites, no electromagnetic signals—and they’re blind.”

  He tapped the cold, thick hull. “This one’s one hundred percent analog. Manual valves. Human hands. If we sink like a rock and hide on the seafloor, no AI on Earth will ever find us.”

  The tale has been stolen; if detected on Amazon, report the violation.

  He ushered Mei inside and sealed the hatch. Inside, faint red emergency lights drifted like ghosts through the narrow, pipe-cluttered corridors. Ethan sprinted to the control room, his eyes scanning the maze of copper valves and mechanical pressure gauges.

  HISSS—!

  Compressed air surged into the ballast tanks. The Nautilus shuddered, coughing like a dying animal, then began its slow descent. The sound of rain hammering the surface faded. Silence, heavy and absolute, closed in.

  “Depth: fifty meters,” Ethan whispered. “Diving.”

  He shut down the diesel engine and switched to the emergency battery-powered electric motor. The propeller turned slowly, guiding them deeper into the abyss. Mei sat against the bulkhead, gripping the hard drive to her chest as if it were her own heart.

  PING.

  A sharp, metallic groan struck the hull. Active sonar.

  “Did they find us?” Mei asked, her voice trembling.

  “No. Wide-area scan,” Ethan said, his forehead beaded with sweat. “But they’ll sweep closer.”

  He began flipping switches—one by one, with lethal precision. Power down. Lights off. Even the red emergency glow vanished. Darkness swallowed the submarine whole.

  “Engines off. Power cut,” Ethan whispered in the pitch black. “Thermodynamic stealth.”

  “What does that mean?”

  “We match our internal temperature to the surrounding water. All heaters off. CO? scrubbers off. Our body heat has to drop until the sensors see nothing but freezing seawater. From now on, we’re dead meat.”

  As the air purification system died, carbon dioxide slowly began to build. Each breath felt heavier, like inhaling lead. Cold seeped into their fingers, numbing them to the bone.

  PING—!

  Closer. Sharper. A Blue Shark passed directly overhead. Through the steel hull, the enemy sub’s high-frequency motors thundered like the footsteps of a distant god. Mei instinctively held her breath.

  In the darkness, Ethan found her hand and held it tight. His palm was cold, but his grip was steady—a tether to reality in the crushing dark.

  The sound of the propellers slowly faded into the distance. Ethan didn’t move.

  “Not yet,” he murmured. “Marcus doesn’t settle for a single sweep. He never leaves a hunt unfinished.”

  Four hundred meters below the surface, in crushing cold and absolute darkness, their heartbeats became the only measure of time. Carrying humanity’s last hope, they sank deeper—into a sea where Marcus’s hounds still hunted.