Dollhouse S02E12

The Hollow Men

 As the group leaves for Tucson to take down Rossum, Boyd attempts to sabotage its efforts by drugging Echo. Boyd uses Topher's trust to serve Rossum's agenda by tricking Topher into finishing his remote wipe/imprinting technology. Anthony and Priya, who were told in the previous episode to spend their last night together, return to the Dollhouse and discover that Boyd has been betraying them all along. Boyd reveals that he has spared the group's lives because he loves them like family. Caroline has a special genetic trait, expressed in her spinal fluid, which allows her to survive the wipes. Boyd watched over Echo and allowed her to be pushed to her limits in order to allow her to form a complete personality, as every time she "survives" a wipe the gene's expression grows stronger, allowing for Rossum to create a "cure" for wiping. Boyd activates Mellie's sleeper programming and she assaults Paul, but is able to fight it off long enough to tell Paul that she loves him, and then kill herself. Echo manages to fight off Clive 2.0, now in the body of Whiskey, before having her final confrontation with Boyd. Topher wins the ensuing fight by hitting Boyd with the mind-wipe tech he created and hates, and Echo uses the now-Dollstate Boyd to as a suicide bomber to destroy Rossum's headquarters. Echo and Paul have saved the world... but the episode's epilogue depicts them fleeing through the apocalyptic future of "Epitaph One."