Alexis Castle sits silently in a darkened living room. She's not alone. A mysterious figure approaches in stealth-like fashion. BLURP, BLURP! Alexis is startled by the laser tag gunshots of her father who is dressed in a ridiculous flashing uniform. Castle finally got the drop on his daughter, who believes it's time they hung up the lasers and started acting like adults. These aren't the only growing pains being suffered by our favorite mystery writer. He believes the best way to survive his now-strained relationship with Beckett is by making their next murder case their final one.
David Locke is a currency trader who was murdered in the parking lot of his office. Perlmutter says the victim died of blunt force trauma to the head, but also explains that the bite marks on his arm were from someone trying rip off his flesh. Fibers from a 19th Century outfit are found at the crime scene. There was bad blood between the victim and a coworker, Charlie Coleman. Beckett and Castle find the disturbed man handcuffed to the radiator in his apartment. Charlie claims he was attacked along with Charlie. Their assailant: a zombie!
Charlie's story doesn't sound all that crazy once Esposito confirms that the bite marks on his arm match those found on David Locke. Surveillance video shows a mysterious figure wandering through the streets near the crime scene. The suspect is wearing haggard old-fashioned clothing. Close-ups reveal that his ensemble isn't the only thing looking well-worn. The gaunt, cut-up up face suggest the killer is, indeed, a zombie. Needless to say, Castle is on top of the world.
The good times continue once Castle realizes that Alexis was playing him yesterday when she told him they needed to grow up. It was all part of her master plan to zap her unsuspecting dad with her laser. As for the case, Charlie is cleared but opts to remain in jail until they catch the zombie. The team learns that David was trying to get back together with an ex named Greta, who says her jealous boyfriend, Tom Williams, was missing from bed during the time of the murder. He claims he was at the all night library studying.