Castle is completely on edge. His daughter was abducted in “Target.” He wants answers as to why the kidnappers have taken Alexis and her friend to Paris. The FBI says it’ll take time before they can take action. That’s not gonna work. Castle knows the girls need help now. The kidnappers call to set up a ransom demand. Sara’s father will pay the money. He insists that Alexis be part of the deal. Street surveillance cameras show a family member in Paris making the exchange. The money is delivered and, after a few tense moments, so is Sara. Castle desperately watches the screen. There’s no sign of Alexis.
Castle heads home to update his mother. At least, that’s what he says he’s going to do. In reality, he jets off to Paris to get back his daughter—alone. Beckett decides she shouldn’t go after him. She knows Castle is acting like a father, but she needs to act like a cop. She’ll work the case from home. Beckett questions Roger Hanson’s girlfriend. She kicks out her chair to show how serious she is about getting answers. The girlfriend leads them to Hanson’s apartment. The place has been tossed. Fortunately, a computer was left behind.
Castle contacts an old Derrick Storm adviser who puts him in touch with a man who works outside the boundaries of the law. His name is Jacque Henri. This guy brings Castle to a blind sound man who determines where Alexis was held by analyzing the Skype message. Henri realizes the place is bugged. He advises the kidnappers to call him or else he’ll come after them. RING! The bad guys agree to let Alexis go. A meeting is set up in a forest. Back in New York, Hanson’s computer hard drive shows surveillance shots of Alexis. Beckett realizes she wasn’t at the wrong place at the wrong time. She was the target.
Henri drives to the exchange site. Castle is beside him with $3 million in ransom money. His phone rings. It’s Beckett. Castle doesn’t answer, as the kidnappers have arrived. He gets a bad feeling in his gut. Something isn’t right. Henri sticks a gun in the back of Castle’s head. He’s selling him out. Henri says he never would have taken the job if he knew who Alexis truly was. This completely confuses Castle as he’s tossed to his knees. A masked gunman takes aim. Castle is going to be executed.
BANG! BANG! BANG! BANG! Castle is baffled to see Henri and the masked gunman dead on the ground. A man steps out of hiding. Castle recognizes him from a sketch of a guy seen at the farmhouse where they first tracked Alexis. Beckett calls again. She tells Castle that Alexis was the target. This mystery gunman blows away the cell phone. He says that’s how the bad guys are tracking him. He then advises Castle to grab his $3 million before they skedaddle. The stranger says his name is Jackson Hunt (guest star James Brolin). Castle thinks it’s made up identity. Hunt confirms that it is.
At Hunt’s place, Castle sees that he has photos of Alexis from when she was young. He also has a clone of Castle’s phone, though this one is safe to answer. A man named Volkov says he’ll exchange Alexis for Hunt. Castle doesn’t understand until Hunt explains that the person who took his daughter did so to draw him out into the open. He knew he would come looking for her because she’s his granddaughter. Jackson Hunt lets Castle know that he’s his long lost father.
Castle’s dad is a longtime spy who didn’t know he had a son until a year after Castle was born. He never made contact because his dangerous job dictated that he have no relationships. That didn’t stop his dad from giving Castle a copy of Casino Royale when he was 10. It’s the book that made Castle want to become a writer. Castle’s dad also greased some wheels at the CIA when his son was trying to get research info. Little things like that made him feel at least a little bit like a father. He’s been checking in on Castle his entire life. Alexis, too. Now father and son must work together to get her back.
Volkov wants revenge on Hunt for killing his wife. They need to attack this bad man’s compound. Castle communicates via walkie talkie with his dad as he sneaks in to disable the power, but is promptly captured by Volkov’s men. He’s brought upstairs where he sees Alexis being held in a cage. Volkov uses the walkie talkie to call Hunt. He has 10 seconds to give up or he’ll kill his son. Hunt says that’s not going to happen because Volkov is the one who will be dead. The walkie talkie sends out a signal. It’s been rigged. Castle tells Alexis to get down. BOOM! Volkov and his men are killed in a violent blast.
The plan was to have Castle get caught so Hunt could detonate the walkie talkie from afar once it was on the inside. After blowing the lock on the cage, Castle and Alexis escape out the back. They don’t stop until they reach the U.S. Embassy. Before the plan was set in motion, Hunt let his son know that he’s always been proud of him. When Castle and Alexis get back to the States, they are welcomed home by Beckett and Martha. A package arrived while they were in transit. Castle sees that it’s a copy of Casino Royale. It’s his dad’s way of letting him know that he’s still out there. Somewhere.