Half a decade after the Dominion War and more than a year after the rise and fall of Praetor Shinzon, the galaxy's greatest scourge returns to wreak havoc upon the Federation—and this time its goal is nothing less than total annihilation. Elsewhere, deep in the Gamma Quadrant, an ancient mystery is solved. One of Earth's first generation of starships, lost for centuries, has been found dead and empty on a desolate planet. But its discovery so far from home has raised disturbing questions, and the answers harken back to a struggle for survival that once tested a captain and her crew to the limits of their humanity. From that terrifying flashpoint begins an apocalyptic odyssey that will reach across time and space to reveal the past, define the future, and show three captains—Jean-Luc Picard of the U.S.S. Enterprise, TM William Riker of the U.S.S. Titan, and Ezri Dax of the U.S.S Aventine—that some destinies are inescapable.

On Earth, Federation President Nanietta Bacco gathers allies and adversaries to form a desperate last line of defense against an impending Borg invasion. In deep space, Captain Jean-Luc Picard and Captain Ezri Dax join together to cut off the Collective's route to the Alpha Quadrant. Half a galaxy away, Captain William Riker and the crew of the Starship Titan have made contact with the reclusive Caeliar—survivors of a stellar cataclysm that, two hundred years ago, drove fissures through the structure of space and time, creating a loop of inevitability and consigning another captain and crew to a purgatory from which they could never escape. Now the supremely advanced Caeliar will brook no further intrusion upon their isolation, or against the sanctity of their Great Work....For the small, finite lives of mere mortals carry little weight in the calculations of gods. But even gods may come to understand that they underestimate humans at their peril.

The soldiers of Armageddon are on the march, laying waste to worlds in their passage. An audacious plan could stop them forever, but it carries risks that one starship captain is unwilling to take. For Captain Jean-Luc Picard, defending the future has never been so important, or so personal—and the wrong choice will cost him everything for which he has struggled and suffered. For Captain William Riker, that choice has already been made. Haunted by the memories of those he was forced to leave behind, he must jeopardize all that he has left in a desperate bid to save the Federation. For Captain Ezri Dax, whose impetuous youth is balance by the wisdom of many lifetimes, the choice is a simple one: there is no going back—only forward to whatever future awaits them. But for those who, millennia ago, had no choice...this is the hour of their final, inescapable destiny.