Deep in the Caribbean Sea, a nuclear submarine is forced to suddenly abort its mission under mysterious circumstances. Strange facts begin to emerge that lead naval investigator, John Clay, to a small group of marine biologists who are quietly on the verge of making history. With the help of a powerful computer system, 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 was sure she would never trust the military again. However, when an unknown group immediately becomes interested in her work, Alison realizes John Clay may be the only person she can trust. Together they must piece together a dangerous puzzle, and the most frightening piece, is the trembling in Antarctica. To make matters worse, someone from the inside is trying to stop them. Now time is running out...and our understanding of the world is about to change forever.