President Martinez and his longtime Chief of Staff (guest star Roger Bart) charge the intelligence community with decrypting Thomas's satellite message, but more importantly determining to whom it was sent. Meanwhile, on the other side of the Capital, Alaskan Senator Catherine Lewis (guest star Virginia Madsen, "Sideways") begins her first day on the job. Sophia has an emotional reunion with Michael Buchanan. Elsewhere, Sean and Leila get a fresh lead on the whereabouts of Samantha, while Dempsey (guest star Hal Holbrook, "Water for Elephants") foretells the future.