When a two-year-old girl is discovered missing from her home, Beckett is called in to assist with the investigation only to discover that the FBI agent in charge is, in fact, her ex-boyfriend. The two of them try to put aside their unresolved feelings as they race to find the girl, but when Castle inserts himself into the investigation, competition quickly heats up for Beckett’s attention.

When a murdered man is found stuffed in the garbage chute of an apartment building and two women arrive to ID his body — one his wife and the other his fiancee — Castle and Beckett have their hands full keeping the women from killing each other as they work to peel back the layers of the victim's double life. Was it a jilted woman, corporate espionage, or a much darker secret that led to his demise?

In the second part of the story begun in "Tick, Tick, Tick," the serial killer remains at large and is taunting Castle, Beckett and Jordan Shaw to catch him

An "Officer Down" call turns out to be a male stripper dressed like a cop. Castle and Beckett explore the world of male strip clubs and struggling actors, all people in pursuit of fame. They need to determine if the murder was because of the victim's dreams of stardom or something more sinister.

A murder has been committed on the set of "Temptation Lane", one of New York's longest running soap operas.

During the investigation of the murder of an Atlantic City casino owner at an abandoned warehouse, strong leads emerge for the team in both New York and Atlantic City. As Beckett and Capt. Gates work the New York leads together, Castle naturally chooses to join the detectives for the road trip to "America's Playground," hoping to help solve the case while throwing an impromptu bachelor party for Ryan.

A devilishly handsome detective from Scotland Yard, Simon Hunt, teams up with Castle & Beckett to find the person responsible for the murder of his friend's daughter. Also, Nigel Wyndham, the Deputy General at the British Consulate whom Castle & Beckett suspect is up to more than just ambassadorial balls and diplomatic luncheons. Meanwhile, Lanie convinces Beckett that she needs to make a move on Castle before it is too late.

On Beckett's first day back from her suspension, she and Castle are thrown into the salacious world of local TV news when WHNY's veteran weather girl is found dead. As if navigating an industry full of backstabbing and ruthless ambition weren't difficult enough, they have to do it while hiding their new relationship from their coworkers

When an up and coming DJ is killed at a pop star's album release party, Beckett and Castle must dive into the raucous world of New York's music industry. Then, when the investigation leads to a troubled teenager, Esposito takes the kid under his wing, hoping to put him on the right track before it's too late.

With Beckett still in D.C., Castle and the boys investigate the murder of former child star Charlie Reynolds, who rose to fame playing the lovable nerd on an early 90s High School sitcom. But the case takes a turn for the strange when Agents Beckett and McCord arrive from Washington to take over the investigation, creating competitive tension in the precinct. But why would a washed-up actor's death warrant Federal scrutiny? Whatever the reason, Beckett and McCord aren't telling. Meanwhile, Castle has to contend with a new face at the 12th, NYPD Detective Frank "Sully" Sullivan.

When the assistant to Modern Fashion Magazine’s dictatorial editor Matilda King is found murdered, Castle and Beckett are thrust into the glitzy, ruthless world of high fashion in their search for the killer. Meanwhile Beckett’s history in the modelling world gets her access to a very special wedding surprise.