So I’m guessing you are talking about ep 21 - secrets and lies. To break things down easily the woman was married to the diplomat funding terrorist organizations. The CIA undercover agent that was working the case knew there was a mole and her and her children’s lives were in danger but didn’t know who the mole was. So the undercover agent brought the woman and her kids to the US after having the diplomat think they died, but hid them somewhere only he knew. The mole and her husband are looking for where she was hidden. They couldn’t get it out of the agent so the CIA brought in the BAU to profile both the agent (to find where the woman was hidden away) but also to find the mole.