Beckett (Stana Katic) and Castle’s (Nathan Fillion) latest investigation is stymied when Homeland Security closes the crime scene of the car bombing. Without a body or a crime scene, Beckett continues the investigation by talking to the victim’s widow (Catherine Dent) and son (Shane Coffey) who believe he was killed for his whistleblowing website which revealed highly damaging documents concerning corporations, politicians, and several government agencies. Things get even more interesting when they discover their victim was killed not from a car bomb, but by an unmanned aerial drone. Despite Castle’s assertions that the drone may have achieved sentience and attacked on its own, Beckett begins looking into where the drone came from and why it was used as a bizarre method of murder.
Looking for answers, Beckett and Castle head to the nearest military base only to be stonewalled while federal agents seize all evidence inside the precinct proving a drone strike occurred. The pair get a new lead when they notice in each piece of the case the same mystery man (Carlos Bernard) keeps showing up. After arresting him, Beckett discovers he’s a special investigator for the Attorney General who confirms the drone wasn’t from Fort Drummond but was a government controlled drone that was hacked and used as the perfect murder weapon, most likely by the batshit crazy engineer who designed their software to begin with (Eric Lange).
Ryan (Seamus Dever) is able to find the scientist through the man’s collection of rare books, but despite being responsible for the software that hacked into the drone he turns out not to be their killer in fact he was working with the writer to expose the danger of unmanned drones. Beckett and Castle then turn their attention to other suspects including the victim’s assistant Omar (Hrach Titizian) and son, both of whom had knowledge of the flash drive with the software as well as motive and opportunity to use it.
It’s certainly not every week you get murder by military drone. Given the limitations on time the episode works well (but a two-parter may have been a better way to go to showcase more of the government stonewalling and the hoops Beckett and Castle had to go through to get their case started). The actual motivations for the murder are also somewhat disappointing (personally I prefer Castle’s “Rise of the Machine” theories to an angry son lashing out). The real point of interest is the offer Beckett receives going into next week’s season finale which would give her the kind of position and responsibility to show off her skills at a national level but might also cost the detective her relationship with the man she loves.