Castle can barely enjoy his cool-renovated office or control Alexis' self-righteous incursion into his PI-business, as Kate goes missing. He finds the inscribed ring he just gave her at the scene of a quadruple murder of apparently unconnected men. He promises to keep the NYPD out for the collaboration of obnoxious, insurance-employed English ex-cop Hayley Vargas, who came to investigate a five-fold identity theft. The trail leads to evidence that Kate wasn't abducted but kept others at gunpoint, and it all connects with cahoots of her mother's murderer, jailed senator William Bracken. Written by KGF Vissers

Becket is on the run with Vikram Singh, the CIA analysis who discovered the identity thefts and their purpose, and under mercenary attack, but gets pulled out by Castle's top-secret agent step-mother. Hayley, confessing guilt, rejoins castle and Alexis. It becomes clear the assailants belong to former senator William Bracken's mighty conspirators, but he's murdered in jail and just about everyone's loyalty is found questionable. Becket decides to spare Castle's family needless risks, against his choice, by going her own way again. Written by KGF Vissers

When the body of a local college fraternity student is found gruesomely murdered, Castle has to go undercover as a professor in order to gain access to the victim's world. However, he and Beckett soon discover that behind the fun and games of college are some darker secrets the university wants to keep hidden.

Blind Catholic priest Arguello identifies the regular prayer murdered in his church as Castle's famously reclusive idol, a one-hit great American novel author. Becket reluctantly admits she needs Castle's author skills and city hall access to investigate the case, as the author's multiple pseudonyms 'for long participatory research purposes' including a mob hit-man lead to infidelity and city funds fraud, triggering new crimes. Meanwhile Ryan and Esposito each hope to supplement their meager family budgets via the NYPD sergeant detective exam. Written by KGF Vissers

A transporter is murdered to steal a priceless Van Gogh, insured by Shipton's company. Castle wriggles into the NYPD investigation by finding how to use the unwilling only witness Mia Laszlo's hyperosmia (pathologically-extreme smell sensitivity). The plot thickens as there is a counterfeit involved, and an obsessive family inheritance factor. Meanwhile Esposito makes sergeant, but Ryan failed the exam and accidentally keeps hurting his partner, who suspects mean jealousy. Written by KGF Vissers

Detective Slaughter returns to enlist Castle's help in solving a high-stakes robbery case. But when a body is found linked to the crime, Slaughter becomes the number one suspect in the heist turned murder, while Castle has to determine whether he's guilty or help to prove he's innocent.

Actor Scott McCoy is stabbed 17 times in his home. Castle 'infiltrates' the team as NYPD psychiatrist-recommended 'buffer' between bickering buddies Ryan and Esposito and is determined to use first anniversary treats to get some quality time with his wife. They find Scott and his wing-man Anton Ford deliberately seduces wives of rich client of a single divorce lawyer. Castle secretly finds out that Vikram Singh is discretely on to something for Becket's quest. Written by KGF Vissers

Castle and Beckett investigate the murder of a cruise ship entertainer, only to find themselves trapped at sea with the killer.

When a corpse is discovered in the theater of Martha's latest show, Castle and Beckett's investigation reveals suprising details about the world of competitive a capella.

Castle cockily reports as sole eye witness in the stab murder case against the caterer at Roger and Joanna Masters' society party where he was hired for a crime novel lecture. Instead of the incompetent pro-bono lawyer, who fell ill, stands in brilliant Caleb Brown, actually suspected by Kate and Vikram in their secret case, who makes Richard admit he could be wrong, again. Castle even gets the team to urgently check out alternative motives, including robbery, a lesbian affair, paternity and blackmail. Written by KGF Vissers

Grigory Mishkin, son of Russian consulate diplomat Sergei, is murdered. Castle gets to investigate, closely 'accompanied' by domineering Russian 'security guard' Vasiliy Zhirov, apparently an spy, who has excellent contacts at State Department and is discretely part of Becket's secret team. They discover that Grigory was killed to prevent him disclosing a larger plot, which still leads to a sniper murder attempt, and dig into further secrets, while one more awaits Castle. Written by KGF Vissers

While Becket's team investigates the murder of Emma Matthews, Castle is abducted with several even more puzzled men to a closed room, where they are challenged by cruel game after sick puzzle. Each puzzle promising a step closer to freedom. Then they discover to be besides an identical room where Becket and women dear to his companions wrestle with similar challenges. While Esposito, Ryan and Alexis independently work on the site, Castle and Becket as natural leaders preside. Also after the groups are joined they are now facing common challenges. Written by KGF Vissers

Beckett and the 12th Precinct look into the murder of an English as a Second Language student. When the victim's class won't talk to the police, Castle goes undercover as a French Canadian immigrant and learns the victim was more than he seemed.

Castle is greatly flattered to be asked by an LA famous detectives club. At arrival, he finds he must earn it by beating cheater Austin Elektra to solve a murdered member's case first. In the process, he finds a Korea town clue to his own lost period, but it also poses a dilemma concerning Becket. Written by KGF Vissers

The killing of a police rookie with an NYPD academy service gun is tied to the present class's female top student, so Becket, the best ever, goes undercover. The trail points to the Irish mob and a mole, who tie in trough love. Meanwhile Castle decides after long hesitation to read the message to himself he warned against and next to tell Becket it points to her nemesis. Written by KGF Vissers

After an armored car driver is killed and some of the money it was carrying stolen, details of the heist start to ring a bell for Esposito regarding a previous theft of gold coins nine years earlier. Also, Beckett officially moves back in with Castle but is starting to feel that Castle's home network AI, Lucy does not have as much love for her as he does.

Castle and Becket fully enjoy conjugal life again. The team investigates the murder of a man who was digging in Turkey for what seems to be Aladdin's jinni lamp and smuggled it home to Manhattan. Castle speculates the person who keeps crossing his path seems the magical ghost while they find the secretive accomplice murdered too. Written by KGF Vissers

After planting a spy bug for a private job, Hayley sneaks off while her partner Marcus Janek stays hidden to spy on the lovers couple from the ICT target firm that nearly caught them. Next morning, team castle investigate the murder of Marcus, fin on that site, yet she stays silent as long as possible. Meanwhile the case is found a cyber terror hazard and MI5 has dispatched agent Steven Mallory, who duly treats her as prime suspect. Written by KGF Vissers

New York City safety inspector Alan Masters inexplicably survives a poisoning already ruled fatal by Lanie's autopsy. Despite police protection, he's electrocuted in his bed, again called dead but very alive. Castle takes Alan home but can't resisting coaching him to date a foxy girl from the research lab he's secretly admiring for long, but she instantly accepts a dinner date, where a mob killer arrives hired to help cover up the loose end in the bribing of incorruptible Masters' colleague, whom he got fired. Vikram Singh finds out that LockSat met basically good Caleb Brown, so Kate bugs him to help set a trap. Written by KGF Vissers

Action movie star Zane Cannon was murdered while rehearsing a Hamlet play co-starring Naomi Fox directed by Elodie, both seriously reputed. The team soon finds links with Zane's ex-con stepbrother Johnny Toro, Guadalajara drug cartel-baron Jorge 'El Oso' Zamacona and his so far clean-reputed brother businessman Hector. Castke gets 'kidnapped' by Jorge, who demands a script glorifying his life. Meanwhile the Broadway scene is proven far from innocent either. Written by KGF Vissers

Castle and Kate must postpone naked Twister to investigate the death of mental asylum detainee Gabriel Shaw, who arrived in Castle's PI office carrying the ax he was fatally slashed with. Shaw, who believes in a divine mission to stop the Antichrist, was probably after the Angels Dagger which Castle discovers in his predecessor Kramer's secret vault. Castle fears a demonic threat while the team looks into the asylum, the missing orderly on whose watch Shaw escaped, tycoon Victor Crowne whom Shaw tried to murder, Kramer's widow and Oscar von Eckland, heir to another Antichrist-fighter. Written by KGF Vissers

As the rest of the team investigates a body found burned in the trunk of a car, Castle, Beckett and Vikram are given instructions from Loksat via the phone for Caleb to deliver a flash drive to Loksat's accountant. Espo later calls Beckett to say the body in the trunk was identified as Caleb. The dropoff is a trap, resulting in a shootout. Castle and Beckett are saved by Mason Wood (Gerald McRaney) of the L.A. detectives' club. Castle goes home to check on his family, while Beckett learns who torched Caleb. Impatient, Castle goes to find Beckett but is captured by Loksat's henchman and is given a truth serum which jeopardizes everyone he has told about Loksat. Beckett is picked up by Mason, who is soon exposed as Loksat. The precinct saves Castle from death, and he must save Beckett from Loksat. Back home safely, Castle is shot by Caleb, who is then killed by Beckett. Wounded, she crawls to Castle. Seven years later, the two enjoy breakfast while their three children play. Written by nishantgoel