With Boyd’s betrayal revealed, the team travels to Tucson to attack Rossum directly. Boyd uses Topher to complete the remote wiping and imprinting technology, and reveals that Echo has a peculiar genetic trait in her spinal fluid that allows her to resist the imprinting process. Every time she is wiped, the trait goes stronger, and Rossum hopes to use her to develop a cure. Boyd activates Mellie’s sleeper programming, who manages to resist long enough to tell Ballard she loves him before killing herself. After a confrontation between Echo and Clyde, Topher manages to wipe Boyd, who the group then rig with explosives and leave. The explosion destroys Rossum and Boyd’s now-empty body, but ten years in the future, it appears that the apocalyptic scenes from Epitaph One have still come to pass.