Telepathic aliens known as the Benefactors pressed humanity to join their cause in a galactic war in exchange for curing disease and eliminating human social divisions. Humans were drafted to fight the World-Eaters, a species of colossal, predatory worms. However, a lost comrade returns to reveal the truth about the war, the Benefactors, and the worms. Led by former convenience clerk Gabriel Contreras, humanity's war for survival has begun.