In the aforementioned following episode, "Linchpin," Sophia turned villainous and revealed herself as the mole behind the "Pandora plot," when she pointed a gun at Castle and Beckett. After her henchman disarmed Beckett, Sophia sent him to kill the young girl. Sophia's villainous plot was all revealed; she killed Nelson Blakely and his contact, Tracy McGrath, who was attempting to stop her plan, and then she killed Gage as well. As for a motive, the evil Sophia claimed that money was involved in setting off a huge war. Sophia laughed evilly and stated--in Russian--that America isn't even her country, meaning that she's a Russian sleeper agent. Sophia was planning to frame Martin Danberg for her own crimes, and taunted Castle by stating that his father was the only reason why he received access to the CIA. Right before she could pull the trigger, Sophia was shot and killed by Danberg.