"Just one year ago Alison Shaw and her team of marine biologists stunned the world with an incredible breakthrough. And now, they're about to do it again.
But an ocean away, something strange is unfolding. Along a lonely coast in South America, an experimental Russian submarine, long thought to have been dismantled, has suddenly resurfaced. And the U.S. Navy has taken notice, sending officers John Clay and Steve Caesare to investigate. The sub has been studying a group of unmarked soldiers, disappearing into the jungle each night beneath the cover of darkness. Something has been discovered... something big. And it's about to fall into the wrong hands. Unless Alison Shaw and her team can find something that no one else can."