[s6e4] Number One Fan -

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

(Tom Amandes): A wealthy businessman who is revealed to be Emma's biological father. Production & Significance [S6E4] Number One Fan

: By the end of the episode, Beckett officially regains her job with the NYPD, ending her brief period of unemployment following her firing from the FBI. Castle season 6 episode 4 review: Number One Fan As Castle enters the clinic to negotiate, he

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. Production & Significance : By the end of

: This episode is notable for being the first time Castle is actually shot; he survives thanks to his "Writer" bulletproof vest.