Kate Beckett's investigation into her mother's death is reactivated when Hal Lockwood (guest star Max Martini, "The Unit") - a professional hitman with knowledge of Beckett's mother's murder - stages a spectacular escape during a court hearing. As police launch a manhunt for Lockwood, Castle and the team uncover evidence of a deeper conspiracy involving a mysterious figure with law enforcement connections who is linked to both Lockwood's escape and the killing of Johanna Beckett. The search for Lockwood and the quest to identify his co-conspirator leads to a shocking and deadly conclusion.
During rehearsal for "Baron's All-American Beauty Pageant," the contestants are shocked to discover the body of Miss Illinois - strangled, but by whom? As Castle and Beckett delve into the cut-throat competition of the pageant world, they learn that a number suspects had motive for murder, including jealous fellow contestants, the pageant's larger-than-life millionaire sponsor, Victor Baron (Michael McKean, "Curb Your Enthusiasm"), and the show's host -- hedonistic TV personality.
While investigating the shooting death of her ex-partner in New York, Beckett comes to believe the suspect has fled to Los Angeles. Against orders, she travels to L.A., going renegade to track down the killer, with Castle unexpectedly along for the ride. As they dig deeper into the motives, they uncover a trail that leads from a rooftop pool in Hollywood to the sandy beach of Santa Monica. Along the way, they visit the set of the "Heat Wave" movie (based on Castle's book) and enlist the cast to help break the case. But as they get closer to apprehending the killer, Castle begins to wonder whether Beckett is out for justice -- or revenge.
When a champion swimmer and Olympic hopeful is found dead in a training pool, Castle & Beckett dive in to investigate his murder, and uncover myriad secrets that might have led to his death. Also in the episode, crime fiction authors Michael Connelly and Dennis Lehane guest star, offering Castle their insights into the case over a game of poker.
Castle & Beckett work the case of a man found dead inside a pizza oven, but it turns out not to be someone associated with the restaurant – it was a reporter. Was his story, “The Pizza Wars,” enough to get him killed, or was it something much deeper than that?
During the high-profile trial of a murdered socialite, a juror suddenly tumbles out of the jury box -- dead! When Castle & Beckett learn the juror was poisoned, their investigation soon uncovers that this seemingly innocent juror may not have been so innocent after
In the episode, a murder has been committed on the set of "Temptation Lane," one of New York's longest running soap operas. Sarah Cutler, the head writer on the soap, has been killed with a fire axe. Castle & Beckett quickly discover that the behind the scenes drama at "Temptation Lane" is just as scandalous as the fictitious storylines, and just about everyone would kill to get ahead. Ultimately, Castle's unique skill set as a writer leads to a discovery about the killer and the secret he or she would do anything to protect.
With time running out, Castle and Beckett must put aside their differences with Agent Fallon (guest star Adrian Pasdar) to avert a city-wide catastrophe.
Castle and Beckett investigate the apparent robbery-homicide of a New York cab driver, only to discover that the victim was involved in a mysterious conspiracy with unimaginable consequences. As the stakes continue to rise, hard-charging federal agent Mark Fallon (guest star Adrian Pasdar) takes over the investigation. Together, Fallon, Beckett and Castle must race to unmask the truth about the victim before it's too late.
Castle and Beckett find themselves on opposite sides of the case when Castle's old school friend (guest star Jason Wiles) emerges as the prime suspect in his own wife's murder. As they work to solve the crime, Castle comes to realize that one of two terrible things must be true... Either Detective Beckett is about to arrest an innocent man for murder, or his old friend is a cold-blooded killer.