A frightened, bloodied woman races out of the woods in the dark of night. She stumbles onto a road where she’s killed by an oncoming truck. Castle takes special notice of the carvings on the dead woman’s face. He recognizes the truck driver’s description of the ghostly, porcelain disguise worn by the person who was chasing the woman. Castle says, “Beckett, I’ve seen that mask before.
Castle recalls the time he was staying with a friend’s family in New Hampshire when he was 11-years-old. He got lost in a place called Hollander’s Woods. Castle saw black-clad figure leaning over something. He would later discover it was a dead woman’s body. She had the same markings as the victim in the current case. The masked figure threatened to kill Castle if he ever mentioned what he saw. The woman’s body was never found. Castle began to wonder if it ever happened. It was this incident that led him to become a mystery writer.
The current victim’s name is Emma Malloy. Her father says she was looking for her friend, Zoey, who disappeared while trying to escape from life with an abusive boyfriend. This missing girl didn’t have any family. No one would have known she was gone if it hadn’t been for Emma. Castle believes the killer targets people he knows won’t be missed. He needs to find this guy. He needs to end this.
The investigation leads Castle and Beckett to a 72-year-old woman named Connie Lewis. She owns the car Emma was tailing. Actually, she “owned” the car. The decayed body of Connie Lewis is found in her home. Lanie says she’s been dead for years. Castle believes that’s why the killer chose to use her car. A call is made to Connie’s son. The guy’s cell phone can be heard ringing nearby. BANG! A gunshot rips through a hidden compartment. Ryan and Esposito give chase to the gunman, but ultimately lose him.
The team’s new prime suspect, Connie Lewis’s son, Noah, has had mental issues and violent tendencies. Ryan discovers that there was a young, female migrant worker who went missing around the time Castle saw that body. The woman was Rosalita Campo. Castle has flashbacks to that fateful day when he first found the body. He remembers when he first started writing. He was just a kid. Alexis is now older than he was then and she currently has no idea what she wants to be. Castle gives her an inspirational pep talk assuring her that she’ll be amazing at whatever she becomes.
Beckett is asked to take part in a performance review. She’s unprepared for the highly-critical remarks hurled her way. She’s chastised for all the times she’s ignored the rules and how her personal relationship with Castle has influenced her actions. Beckett is told she’s not fit for a captaincy position and may not even be qualified to be a police detective. It’s a jarring verbal smackdown. Beckett is speechless, but only for a moment. She gives an impassioned declaration as to why she does what she does. This is just what her reviewers were hoping would happen. This was her audition. They want Beckett to run for New York State Senate.
Beckett and Castle discuss the future on the swing set at the park. A decision needs to be made soon. But first they need to solve their latest case. Noah is captured, but he isn’t talking. No connection can be made between him and the murders. He can’t even be linked to Hollander’s Woods back in 1983. A trip is made to see Noah’s psychiatrist Dr. Van Holtzman. Castle believes he recognizes the shrink’s voice as the same killer who threatened him in the woods.
Nobody believes in Castle’s theory that Holtzman is behind the killings. Beckett apologizes for that. She believes him now. They need to figure out how the killer made his victims disappear. There’s a barn on some farmland that Holtzman owns. Beckett doesn’t have enough for a warrant. That’s why Castle needs to search the place as a trespassing private citizen. He finds evidence including the mask he saw and photos of the victim.
The barn door closes. The killer is there. Holtzman realizes that Castle is the boy from the woods all those years ago. Beckett races to the barn, but she can’t get in. The masked killer tackles Castle. He holds a knife to his throat. Blood trickles down as the blade slowly penetrates the skin. Castle screams for Beckett. He places his hand under an opening in the barn door. Beckett hands him her gun. BANG! BANG! BANG! BANG! Castle shoots his attacker dead. The porcelain mask shatters on the ground as the killer’s lifeless body drops.
A short time later, Castle wonders if he’d be the person he is today if it wasn’t for that time in the woods with a killer all those years ago. Beckett assures him that they aren’t where they are because of Holtzman. They are there because of who they are in the face of people like him. That why he writes mysteries and that’s why she became a cop. They are both trying to bring justice to this world.
Castle is the recipient of the Poe’s Pen Career Achievement Award. His good friend, author Michael Connelly, presents him with his trophy. Castle gives a speech mentioning how he’s been thinking a lot about how he got to where he is. He pays tribute to all the special people in his life. He singles out Martha, Alexis, Ryan and Esposito and, of course, Beckett. She’s his muse. She’s the love of his life. Always. Castle makes a toast to his family and friends. There’s barely enough time to take a sip of champagne when Becket’s phone rings. There’s been a murder. Just like that, it’s time for everyone to get back to work.