A serial killer is after women and dressing them up like fairy tales characters.

Tropes

• Artistic License: Martha has a ghost writer helping her with her autobiography. It's... not accurate.
• "Could Have Avoided This!" Plot: When the team confirm that Darren Thomas, the brother of past victim Curtis found out what happened to his brother, Kate points out that he could have told the police, but he dismisses that on the grounds that the police already failed his brother once, even though they have been doing well on the current investigation.
• Creepy Doll: The first suspect is an octogenarian with an apartment full of ivory dolls. Ryan and Esposito are uncomfortable.
• Gender-Blender Name: The first suspect is named "Jamie". She is confused for the serial killer.
• He Knows Too Much: Charlotte killed her friends so they wouldn't reveal about the car accident.
• I'm Standing Right Here: Castle protests that he's sitting right there when Martha's one-woman play accuses him of ruining her life... then she says that being his mother was the greatest role of her life... then she says he could have done a better job of being her son.
• Parental Sexuality Squick: Martha slept with Rick's first publisher. Okay, it was after he got published, but the guy was Rick's age and Martha lets him know that she needs a younger man's energy.
• Pursued Protagonist: The episode begins with the first victim running through Central Park before being struck with a wolf's paw. Lanie's medical examination later reveals that she woke up suddenly after being drugged and taken to the crime scene.
• Revealing Cover Up: By killing both of her co-conspirators, the killer draws the police straight to her.
• Rule of Symbolism: Castle observes that the choice of costumes and the style of the murders is staged as though the killer is choosing to take away the victims’ Happy Endings, such as staging the Red Riding Hood death to look like she was killed by a wolf.
• Single Tear: When she's finally revealed, Christina sheds a tear while bemoaning the fact that the only thing that gave her away was the bows she tied.
• Strictly Formula: I Know What You Did Last Summer, but in NYC, lampshaded by Castle.
• Wounded Gazelle Gambit: Charlotte tried to pass herself off as another victim, but Castle and Beckett noticed two things off: her bow wasn't tied like the other girls, and she had a lower amount of drugs in her system.