Alex Lannon journeys to the legendary city of New Delphi, a human enclave with a dark secret, hoping to secure a military alliance with its mercurial leader. Back in Vega, Claire Riesen faces an uprising against the City's rigid class system, pitting her against the disgraced David Whele and his newfound rebel allies. While war rages in the few cities left on earth, Michael stumbles upon a mystery in the form of Mallory, a town seemingly untouched by mankind's celestial war.