The episode 14 of "Castle" Season 6, "Dressed to Kill," opens with a young man and a young woman searching a dumpster to find fabric for a mid-term couture project. Along with a fabric, they also discover a dead body in the dumpster. The murdered victim's name is Ella Hayes, a personal assistant of Matilda King, the dictatorial chief fashion editor of Modern Fashion Magazine. The culprit looks like he has strangled Ella to death, using a scarf.
Martha is helping Beckett with wedding gowns, showing her the wedding magazines. Beckett is unsure if the wedding gowns featured in the magazines are what she prefers. However, one of the magazines helps Castle and Beckett agree on a wedding venue, the Cordova House. Before they can discuss further, Beckett receives a call. It is time for murder investigation. Lanie informs Beckett that blue hair strands have been found on the victim's neck. Esposito provides information about the victim.
Castle and Beckett visit the Modern Fashion Magazine. Matilda recognises Beckett in an instant. To his surprise, Castle comes to know that his fiancée has a 15 min of modelling history. Matilda informs a clueless Castle that Beckett had passed the offer to model for the magazine's spread page in 1999 -- Nicole Kidman was on the cover.
Unaware about Ella's death, Matilda informs Beckett and Castle that she had fired Ella, as she was messing-up with her schedules. Learning about Ella's death, Julian Bruckner, one of the men from the editorial team, points a finger at Grace, one of other assistants of Matilda. Matilda informs the investigating duo that she had fired Grace, as well, because she had allowed Ella to commit the mistakes. Julian tells Beckett and Castle that Grace and Ella had a nasty cat-fight at a photo shoot, after they both were fired.
The photographer of that photo-shoot had captured that fight. The photos reveal a blue scarf on Grace. She tells Beckett that everyone at the magazine has the scarf, as it is Christmas present. Grace tells Beckett that she witnessed an altercation that took place better Ella and an unknown man, outside the office, a few days ago. Based on her information, a sketch is prepared of the man.
Ryan and Esposito find a bug in Ella's apartment. The building manager provides the information that an exterminator had visited Ella's apartment, some time ago. However, the company listed by the exterminator cannot be found. A lady had seen a man, keeping a watch, some blocks away from the dumpster. Her description matches that of the man, with whom Ella's had an argument outside her office building.
Beckett and co are able to identify the unknown man, with the help of his club tie. He is Marcus Conway, a lawyer working for a top law firm. He is also associated with Couture Chic, one of the biggest competitors of Modern Fashion, as general counsellor. Marcus and editor-in-chief of Couture Chic, Gloria Robbins, inform that they were looking for information on Fashion Magazine's digital expansion plans, after its take-over a month ago by Glenn Carter.
Marcus agrees that they had an aggressive argument when Ella had turned down his offer, but he never contacted her, again. However, Ella had called him after she was fired from her job, saying she has "bombshell information" that can destroy Modern Fashion. However, she did not turn-up. Gloria and Marcus have no role in bugging Ella's place.
Ryan and Esposito dig-out information that the bugging device was brought by James Kavanaugh, the head of security at Modern Fashion. Castle goes to the Cordova House to take a look at the place and for a possible booking, while Beckett questions James.
James find himself caught when Beckett tells him that the building manager identified him as the exterminator. James confesses to bugging Ella's place but not killing her. He tells Beckett and Esposito that Ella's place was bugged on the orders of Matilda, and that it has become a common practice after Carter's take-over of the magazine. All the information from the bug device is transferred to Matilda. Also, Beckett and co come to know that Matilda had run out of the Magazine's building after Ella had made a call to Marcus.
Beckett confronts Matilda. The latter confirms that she had ordered the installation of bugging devices at her employees' houses. It was done to test her employees' loyalty, but done with their permission. The employment agreement has that condition in fine prints. However, Matilda has no clue about the explosive information. Also, she had to rush out of the building because she was late for drinks, with Oscar De Lenta. Matilda says that she is too busy to check the information, recorded by the bug device, on week days. Her alibi checks out.
Esposito decodes the audio-files. One of the calls leads Beckett and co to a tech guy, working at Modern Fashion. The tech-guy tells that someone was changing Ella's schedules for Matilda. She never committed any mistake and was set-up. The changes were made by someone outside the magazine building. The IP address leads to a fashion studio.
Beckett again meets Matilda. She tells her that someone else, and not Ella, was messing with her schedule calendar. Matilda does not know why someone would set-up Ella, but she knows why someone would like to see her fall after the takeover. As a model did not turn-up and a decision has to be made about a dress -- to be featured in the upcoming issue -- in half an hour, Beckett agrees to wear it. Matilda sees Beckett in the wedding gown and comments that she will make a beautiful bride.
Beckett is glowing and has a big smile on her face when checking herself in a mirror. However, her mood soon changes and she becomes contemplative. Castle calls her to inform that the Cordova House is available for fall 2015. But, since a couple broke-up, there is a 2014 spring date available. Castle wants to pay for the available date, but Beckett sounds non-committal. Later, she tells Castle that they should not hurry-up things.
The fashion studio is of a fashion called Mi Yu. Ella had gone to his studio before her death. It turns out the designer has stolen one of Ella's designs. His winning fab-five design was Ella's design. The messing-up of Matilda's schedule was done to make Ella's truth a lie and to discredit her. However, Mi Yu is not the killer, as he never left his studio. However, he made half a dozen calls to someone in Modern Fashion after his confrontation with Ella.
The Fab-Five revelation would have destroyed Matilda and everyone involved. The other person who knew about the stolen design is Julian. Yu Mi revealed to Matilda that it was Julian's idea to change her calendar. Julian has also been gunning for Matilda's job. He changed Matilda's calendar to discredit Ella and undermine Matilda. He turns out to be the murderer.
In her apartment, Beckett sees a gift waiting for her. It is the wedding gown from Matilda. There is a note, as well. It reads: "Kate, this dress looks better on you that it ever could on the pages of a magazine. You'll make a beautiful bride."
Beckett visits Castle. She tells him that, she remembered her mother when she saw herself in the wedding dress. She missed her mother and at that moment, Beckett was not sure whether she can do the wedding preparations, without her mother by her side. Beckett tells Castle, that is why she had said no when he had called-up to discuss the wedding venue date. Castle understands and calls it human. Beckett believes that her mother would have loved Castle. She tells Castle that she does not need any more time. She is ready to get married in spring and find a new venue. She already has the wedding dress.
Castle and Beckett kiss.