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.  

One small handwritten letter, sent from a dark, remote corner of the planet and lost in the system for 60 years, is about to change the entire human race. Outside Denver, Colorado, Joe Rickards stands over a small aircraft wreckage, studying burnt remains still smoldering in a field of freshly fallen snow. He's an investigator for the NTSB, working to carefully roll back the last several hours and identify the cause of the accident. But this time, he can't.

Navy SEAL Keith “Chunk” Redman has been one of the military’s top doorkickers since the day he pinned on his trident: loyal, single-minded, lethal. Tasked to lead a new, covert team of Tier One SEALs—the most elite special operators in the world—Chunk can no longer simply rely on the status quo. To safeguard America, he needs help to stay a step ahead of its adversaries.

En route to London from New York, Flight 305 suddenly loses power and crash-lands in the English countryside, plunging a group of strangers into a mysterious adventure that will have repercussions for all of humankind. Struggling to stay alive, the survivors soon realize that the world they've crashed in is very different from the one they left. But where are they? Why are they here? And how will they get back home?

Geophysicist Jack Greer believes he may finally have found the resting place of the meteorite that wiped out the dinosaurs 65 million years ago. A few miles off the Yucatán coast, Jack and a team of scientists tow an aging drilling platform over the impact crater with the aim of securing a sample. But buried deep beneath the earth lies a shocking discovery that threatens to shatter everything we think we know about our species.