When an old American operative is gunned down in Russia, Arthur pays a visit to a Virginia super-max prison. While there, he speaks with a former spy, Max Langford, who is serving a life sentence for treason. Arthur walks away from the meeting positive that Langford is behind the hit in Moscow.
This all means that Annie is torn away from a marathon she was to run with her sister and placed on the operation instead. Joan briefs the team at Langley and tells them to demolish the intel ring that Langford is running out of his prison cell. The focus is Langford's two daughters, Grace and Bebe, the only two people who have spoken to him at the prison.
Annie's assignment is Grace, a horse veterinarian. In order to get close to her, Annie will have to pose as a journalist for a horse magazine. Grace is apprehensive at first, but eventually allows Annie access. And after tailing Grace to a clandestine meeting in the woods, Annie finds the "veterinarian" handing off intel to an infamous arms dealer named Adnan Al-Raheeb. It looks like treason runs in the family.