M1, T11: President Martinez (Blair Underwood) and his longtime Chief of Staff (guest star Roger Bart, "Desperate Housewives") charge the intelligence community with decrypting Thomas's (Clifton Collins, Jr.) 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 (Laura Innes) has an emotional reunion with Michael Buchanan (Scott Patterson). Elsewhere, Sean (Jason Ritter) and Leila (Sarah Roemer) get a fresh lead on the whereabouts of Samantha, while Dempsey (guest star Hal Holbrook, "Water for Elephants") foretells the future. Zeljko Ivanek, Ian Anthony Dale, Bill Smitrovich, Taylor Cole, and Lisa Vidal also star.