: The episode was written by Terence Paul Winter and directed by John Terlesky.
(Stana Katic): Castle's fiancée, who at the start of the episode is technically out of a job but assists the team in the investigation. [S6E4] Number One Fan
(Tom Amandes): A wealthy businessman who is revealed to be Emma's biological father. Production & Significance : The episode was written by Terence Paul
As Castle enters the clinic to negotiate, he begins to believe Emma's story despite incriminating evidence found at the crime scene, such as a murder weapon from her own kitchen and suspicious text messages. While Castle works the inside, Detective Kate Beckett and the rest of the team investigate from the outside to uncover the true killer. Key Characters & Cast Production & Significance As Castle enters the clinic
( Nathan Fillion ): The writer-turned-investigator who must use his wits to keep the hostages safe and solve the case.
A young woman named (played by Alicia Lagano) wakes up to find her boyfriend, Angelo Vasquez, murdered in her apartment. Panic-stricken and fleeing from the police, she ends up in a dental clinic where she takes several people hostage. Emma refuses to negotiate with the police, insisting on speaking only to Richard Castle. She claims to be a fan of his work and trusts only him to prove that she has been framed for the murder.