The third novel in the series that began with instant New York Times bestseller Axiom's End, this alternate history first-contact adventure deepens the exploration of a world faced with extraterrestrial intelligence.

First Contact has not been going well. The nations of Earth are rapidly militarising against the arrival of the Superorganism, an alien civilisation that promises to destroy humanity before it can develop into a real threat. The Superorganism has done it before to their distant transient relatives, the rebel Superorganisms and they could easily do it again. But the alien Ampersand and his human interpreter and liaison Cora Sabino are done with trying to save humanity from both the Superorganism and itself; to them, this is a civilisation that does not deserve to be saved.

When a strange new form of communication between the two of them reveals to Cora how alien Ampersand truly is, she begins to question her blind devotion to say nothing of the wisdom of fleeing Earth with him. But she soon learns of a danger that may force them to leave before either of them are ready: a group of superorganism enemies that been wreaking havoc on Earth for decades. Existence on the margins has made them desperate, hungry, and bent on revenge against any of Ampersand's race whose path they cross.

Before Cora and Ampersand can make their final escape, these hostile aliens stage an attack, and take that which is most dear to both of them. Ampersand's enemies will not consider any form of truce; the greatest threat to them is not from the Superorganism, but from an increasingly fearful and violent human civilisation newly aware of their existence, and they will not hesitate to destroy humanity before it destroys them.

Cora and Ampersand must go to extreme measures to take back what was stolen and prevent wholesale human extermination but in doing so they may be no better than the civilisations they are trying to escape.