In part one of the annual two-parter...

• A man is pushed out of a window after being shot, stabbed, and choked. Castle and Beckett are on the case.
• The body goes missing from the morgue and the man they bring in as a suspect, Thomas Gage, escapes out of the precinct dressed as a police officer.
• Gage is a former CIA agent, who went rogue. 
• Sophia Turner, a CIA agent, sends for Castle and Beckett, bringing them to the agency. Tells them about Gage and what he is capable of. They believe he is working to start a catastrophic event.
• Gage’s next victim is a woman named Tracy. Beckett and Castle hunt down clues and find her car, where Gage locks them in the trunk.
• The trace a phone call that Tracy had made to a professor Nelson Blakely. Blakely was supposed to be dead.
• Castle and Beckett track down the professor who clues them into what Pandora is. He had provided information about weaknesses in the US security, dealing with the economy. He realizes that Gage and co. are nearby and runs out of Beckett’s car, only to get shot. A car then pushes Castle & Beckett’s car into the water.
• Alexis is working as an intern for Lanie.