After years of fighting the Locust Horde for survival, the Gears of the Coalition of Ordered Governments have stopped the Locust at great cost. Fleeing to the island of Vectes, the few survivors briefly find peace and hope for the future; but soon Vectes comes under attack from the Lambent, a mutating life-form that destroys everything in its path. Marcus Fenix and the Gears must decide whether to fight to extinction, or flee to the wastelands to live like the Stranded. But Coalition chairman Richard Prescott still harbors one more secret about the Locust, the Lambent, and the future of mankind.