A quarter-century of tentative coexistence among humanity's three superpowers fractures when a political assassination eliminates the Coalition President and ignites simmering territorial ambitions. Three commanders find themselves thrust into the escalating chaos: Dominic Maddox, a United Earth Federation officer whose loyalty wavers due to his marriage to an Illuminate woman; Thalia Kael, determined to revive her people's lost dominance; and Ivan Brackman, a cloned Cybran operative bound to his creator's will. As their individual pursuits collide across the battlefields, they gradually piece together the existence of Gauge, a shadowy figure orchestrating events from the shadows, and stumble upon evidence of Shiva Prime—an archaic superweapon capable of planetary transformation and the potential catalyst for all-consuming interstellar warfare.