One of the greatest breakthroughs in human history. A secret that was never supposed to be found. A crisis that cannot be stopped. Deep in the Caribbean Sea, a small group of marine biologists are quietly on the verge of making history. Alison Shaw and her team are preparing to translate the first two-way conversation with the planet's second smartest species. But the team discovers much more from their dolphins than they ever expected when a secret object is revealed on the ocean floor – one that was never supposed to be found. Alison must quickly piece together a dangerous puzzle, and the most frightening piece is located in the depths of Antarctica. Now time is running out... and our understanding of the world is about to change forever.