Castle and Beckett make their move against LokSat. However, an unforeseen complication puts their plan - and their lives - at risk.
- All Your Base Are Belong to Us: Castle and Beckett took security measures for Castle's office and a couple of other locations, but not for their own shared apartment. They return home to relax, and find themselves under attack by a home invader.
- Babies Ever After: The final scene shows Castle and Beckett with their three children at breakfast together.
- Back for the Dead: The episode opens with Caleb stuffed in the trunk of a burning car. Or so we're led to believe.
- Call-Back: Mason refers to his activities at the Greatest Detective Society as one of his hobbies.
- The Cavalry: Just when the mercenaries appear to have Castle and Beckett pinned down, Mason arrives and picks them up in a taco truck. Ends up being a delayed case of Cavalry Betrayal when Mason turns out to be the head of LokSat.
- Cold Sniper: When the dead drop turns out to be an ambush, Hayley immediately gets to work and calmly takes out several mercenaries with her "guitar."
- Cliffhanger: The episode proper ends with Castle and Beckett bleeding out on the floor of their apartment after being shot by a still-living Caleb. Given that the series was cancelled at the end of the season, the cliffhanger was resolved by adding a short ending scene set seven years after showing the couple alive and well with their three children.
- Crazy-Prepared: Mason had an electromagnet installed in the ceiling of the incinerator room to suck away any guns made of metal.
- Distant Finale: The final scene takes place seven years after the rest of the episode.
- The Dog Was the Mastermind: For the entire season, Beckett and Castle were searching for the Big Bad who was connected to several of their past foes, and was responsible for the murder of Beckett's former partner. The Big Bad turns out to be Mason, an amateur detective who Castle had only met once in a previous episode and who Beckett had not even heard of until this episode. He barely had speaking lines outside this episode.
- Faking the Dead: Caleb was still loyal to LokSat and they faked his death at their hands to set their countermove in motion. At the very end, he shows up to try to finish the job.
- Internal Reveal: Vikram reveals the existence of LokSat to Ryan and Esposito, while Beckett fills them in on the details.
- Lured into a Trap: The dead drop turns out to be a trap set by LokSat, as Esposito identified Caleb as the Victim of the Week.
- More Dakka: LokSat's mercenaries are very liberal in their ammunition use. The final shootout between the NYPD and the mercenaries at the CIA blacksite involved a lot of bullets being fired as well.
- Not My Driver: Castle hails a taxi to take him to the 12th Precinct. Unfortunately, said cab happens to be driven by Mason's lieutenant, Mr. Flynn, who knocks Castle out and takes him to the CIA blacksite.
- The Reveal: The man behind LokSat was none other than Mason, known to Castle as the head of the GDS.
- Series Finale: The last episode of the series as a whole, as ABC cancelled the show.
- Shock-and-Switch Ending: Mason's operation has been taken down and Castle and Beckett can finally relax. As Castle prepares to make breakfast, he wonders why Mason didn't just incinerate Caleb when he had him killed. His thought is cut-off as Caleb shoots him in the chest and he crumples to the floor. Beckett comes out of the bedroom and shoots Caleb dead for real, but she takes a shot to the hip and collapses as well. They crawl over to each other and hold hands as they slowly bleed out. The ending scene shows them alive and well seven years later.
- Time-Compression Montage: The transition from the final scene of the episode and the epilogue seven years later has the camera go past the wall into an empty apartment into an apartment filled with toys and stuffed animals while a snippet of Castle and Beckett's ending conversation from the season premiere plays in the background.
- Truth Serums: Mr. Flynn administers a truth serum to Castle to make Mason's interrogation easier, and it works without a hitch.
- Undying Loyalty: A major plot point for Ryan and Esposito in this episode. They did not learn about Beckett's secret war until this episode, but they both volunteer for suicide missions in order to keep her safe. They were loyal to her for most of the series, but they now seem willing to die for her.
