The year is 3326. Nigel Sheldon, one of the founders of the Commonwealth, receives a visit from the Raiel—self-appointed guardians of the Void, the enigmatic construct at the core of the galaxy that threatens the existence of all that lives. The Raiel convince Nigel to participate in a desperate scheme to infiltrate the Void. Once inside, Nigel discovers that humans are not the only life-forms to have been sucked into the Void, where the laws of physics are subtly different and mental powers indistinguishable from magic are commonplace. The humans trapped there are afflicted by an alien species of biological mimics—the Fallers—that are intelligent but merciless killers. Yet these same aliens may hold the key to destroying the threat of the Void forever—if Nigel can uncover their secrets. As the Fallers’ relentless attacks continue, and the fragile human society splinters into civil war, Nigel must uncover the secrets of the Fallers—before he is killed by the very people he has come to save.

The planet Bienvenido is in crisis. It has finally escaped the Void, emerging into regular space. But it's millions of light-years from Commonwealth assistance, and humans are battling the Fallers for control of their world. This rapacious adversary, evolved to destroy all sentient life, has infiltrated every level of human society—hijacking unwilling bodies so its citizens fear their leaders, friends, and family. A mysterious figure known as the Warrior Angel leads a desperate resistance. She's helped by forbidden Commonwealth technology, which gives her a crucial edge. But the government obstructs the Angel's efforts at every turn, blinded by prejudice and technophobia. As Fallers also prepare to attack from the skies, she might need to incite rebellion to fight this invasion. But the odds seem impossible. Then astronaut Ry Evine uncovers one last hope. On a mission against the enemy, his spacecraft damages an unidentified vessel. This crash-lands on the planet carrying unexpected cargo: a baby. This extraordinary Commonwealth child possesses knowledge that could save them all. But if the Fallers catch her, the people of Bienvenido will not survive.