Following the Advance team, the Exodus ship heads toward a new homeworld. Here they will build a future without the threat of mutated changers. Chief Engineer Adina Vantressa, responsible for keeping the Exodus vessel operational, stays far away from her vast family. She doesn't trust them. Nurse Briar Lindemay shares a secret with her younger sister Caya, an unregistered changer whom Briar has unlawfully brought with her aboard Exodus.

Adina and Briar meet, and their attraction grows despite their attempts to stay apart. Briar fears that acting on her feelings will take her focus from Caya. Adina's emotional scars hinder her, but she can't ignore how Briar makes her feel.

When disaster strikes and the only way to save the Exodus is to trust what the people aboard fear most, will the authorities listen? Or is the journey over and everything lost?