The ultimate novel of the Forerunner Saga trilogy by science fiction legend Greg Carry—set in the Halo universe and predicated on the brand new York Times bestselling video game series!

One hundred thousand years ago. Chaos rules the ultimate days of the Forerunner empire. The Overflow—a horrifying, shape-changing, and unstoppable parasite—is here in force, aided by unexpected allies, and inner strife provides desperately weakened Forerunner defenses. Facing the imminent collapse of their civilization, the about HALO: Silentium Forerunners referred to as the Ur-Didact and the Librarian reveal what they know about the romantic relationship between the long-vanished race from the Precursors as well as the Flood. As the Precursors made many technological varieties, including those of the Forerunners and mankind itself, the roots of the Flood may be within an work of tremendous barbarity, carried out beyond our galaxy ten million years before. Due to that savagery, a greater evil looms. Just the Ur-Didact as well as the Librarian—husband and wife pushed into eager conflict—hold the keys to a solution. As they encounter the consequences of the mythic tragedy, one of them must today commit the greatest atrocity of all time—a shocking act designed to prevent an crazy abomination from dominating the complete galaxy…