Cass's past smashes into his present when he finds a note threatening to expose his real identity. Stella and Tate must now face the prospect of another, superior, hostile life force on Carpathia and discover a way to communicate with it.

A new virus - C24 - hits Forthaven. Berger seizes his opportunity, blaming the virus on the ACs, and exposing Fleur's true origins in an attempt to undermine confidence in President Tate.