(Part 1) Castle and Beckett Investigate the murder of a New York taxi driver who was shot to death, and his taxi stripped of its parts. As they search for his killer, they are led to a storage with trace amounts of radioactive material and evidence that there may be a terrorist group building a dirty bomb. Beckett and the squad must cooperate with a ruthless Homeland Security agent Mark Fallon (Adrian Pasdar), but Castle senses that they have been set up. As Castle and Beckett close in on a suspect, they are trapped in a freezer while a nuclear device is loose in the city.
Tropes:
- Agent Scully: Mark Fallon.
- Blackmail: Amir and his family are being forced into the bombing scheme through threats.
- Cliffhanger: The episode ends with Beckett and Castle discovering an armed dirty bomb, then being locked in a deathly cold freezer.
- Frame-Up: Amir is being framed as a Mad Bomber.
- How We Got Here: The episode opens with men in hazmat suits dragging Castle in to a ... place, obviously an emergency setup made of plastic. Castle begs them to "Just tell me how serious it is!", and they leave him in a room with Beckett. Cut to "36 hours earlier".
- Jerkass: Beckett lays it out about agent Fallon.Castle: What do you think about him?
Beckett: As a cop? Smart, driven. As a person? Kind of a douche. - Jurisdiction Friction: Agent Fallon of DHS takes over the investigation the second it looks like it involves Muslim terrorists detonating a dirty bomb in NYC.
- Layout of a Season: Each of its three full seasons has a major two-parter with a big guest star representing a federal agency right about this time. In this season, we have "Setup" & "Countdown", guest starring Adrian Pasdar, playing a member of the Department of Homeland Security.
- Pulling the Thread: Castle refuses to believe that dedicated, hard-working, new father immigrant Amir is a terrorist.
- Special Guest: Adrian Pasdar, famous at the time for the smash hit Heroes shows up as a DHS agent specializing in terror threats.
