In an episode inspired by The Devil Wears Prada, Beckett (Stana Katic) and Castle (Nathan Fillion) investigate the murder of one (Meredith Richardson) of two (Emily Wilson) former assistants to the notoriously hard-to-please fashion designer Matilda King (Frances Fisher) after they were seen having a public altercation following their termination. After Ryan (Seamus Dever) and Esposito (Jon Huertas) find a bug in the victim’s apartment placed there by a former member of the Special Forces (John Eric Bentley) the mystery deepens.
Beckett and Castle talk with both the lawyer (Paul Cassell) for the fashion magazine’s biggest competitor, who was trying to pressure the victim into providing them inside information, and a fashion designer on the verge of his breakthrough whose studio the victim visited on the night of her death. Despite both having motives, neither turns out to be their killer. However, there was one member (Rob Estes) of the victim’s fashion magazine who can’t make the same claim.
The murder of the week works well, and “Dressed to Kill” finally clues in Castle on Beckett’s short-lived modeling career (a subplot that was brought up a few seasons back but hasn’t been discussed since). While finding the perfect dress and wedding venue Beckett suffers a moment of hesitation for her impeding wedding. Although the show momentarily teases it as a possible obstacle for the couple to overcome, it’s merely Kate coming to terms with the fact that the wedding is coming and that her mother won’t be a part of it. Despite her brief hesitation, the couple appear ready to wed, possibly even before the end of the season.