Dollhouse S01E05

Gray Hour

 Echo is sent on a high-tech heist to recover stolen art for the Greek government, but the job goes badly when one of her accomplices double crosses them. It gets worse when, during a phone conversation with Boyd, she is remotely "wiped" by an unknown party and returns to her child-like state without any of the skills she had been imprinted with. With help from Sierra and Boyd, Echo barely manages to escape. Topher suspects only Alpha could have managed the remote wipe, and finally DeWitt confides to him that her security had indeed failed to kill Alpha.