With Earth on the brink of war with Ada's homeworld, the Alliance has reached crisis point. While Ada faces the truths her guardian, Nell, kept from her all her life, Kay faces the backlash from his father's last, terrible act as a council member. Nobody can be trusted, and betrayal lurks at every corner.

As the inevitable cross-world war threatens everything they care about, Ada and Kay must make devastating choices. If the Alliance falls, so does the Multiverse. And this time, there's no going back...

Nexus is the final book in the Alliance series.