I believe I watched just one season of this TV show.  A young girl is found abandoned at or taken to a FBI or CIA office.  A young female agent is tasked with trying to find out who she is. The girl is very smart and seems to hiding something. I believe in the last episode of the season, it kind of alludes to the young girl as being a unknown family member of the agent, or even possibly a clone of the agent. That’s all I can remember. Thanks!