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A secret facility, the Dollhouse, erases the personalities of Echo and her fellow "actives" so they can assume any relevant personas they may be assigned in engagements that cater to the wealthy, powerful and well-connected. After each assignment, the actives are subjected to another personality wipe so they can enter the next scenario with no memory of an earlier one. At least, that's the plan -- but as the series unfolds, Echo's memory begins to return, and she slowly starts piecing together her true identity. Wikipedia