In the first of a two-part Castle event, Castle and Beckett hunt a ruthless killer who is, as they discover, part of a sinister and international conspiracy. Does this have ties to the murder of Beckett's mother? The detectives are joined on the case by Sophia Conrad (guest star Jennifer Beals), a smart and sexy CIA agent who shares a complicated past with Castle. "Pandora" will air on Monday, February 13 at 10pm on ABC.