Dale Tanner appears to be waiting for someone as he paces the sidewalk of a busy New York street. He notices a black sedan in the distance as he gets into his car. BOOM! Tanner’s vehicle explodes in a firestorm. When Beckett tries to get close to the crime scene, Homeland Security shuts her down. She tries to talk to the two men who were doing surveillance at the time of the explosion. Castle thinks they look like the Men in Black. Agents J and K aren’t talking. Beckett notices another mysterious figure casing the crime scene. She has no idea who this guy is.
Tanner’s widow says her husband started a website for whistleblowers. He exposed lots of scandals and had a partner. Tanner’s son, Sean, thinks his dad’s murder will be covered up. The team learns that Tanner was having an affair with a security contractor who was trying find out who was leaking info about her company. This woman says his wife threatened to kill him when she found out about the affair. The widow insists Dale’s work got him murdered. She may be right. The team learns that Dale Tanner’s car was hit by a missile from a drone.
Castle and Beckett visit Fort Drummond to meet with the head of their drone program. The military men there give no answers to their questions. Everything is classified. Beckett recognizes the mystery man from the crime scene in another room. She promises she’ll find out what’s happening even though the feds have seized all evidence. The team uses a phone number they obtain from Sean Tanner to set up a meeting with the victim’s partner, Omar, who says he was Tanner’s assistant. Beckett subdues a man who is tailing them. He happens to be the mystery fellow she saw at the crime scene and at the military base.