Castle Wiki
Need To Know
Season 6, Episode 3
Air date October 7, 2013
Written by Elizabeth Beall
Directed by Larry Shaw
Episode guide
"Number One Fan"
Castle Group Photo Season 6.jpg
Season 6
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Need To Know[1] is the third episode the sixth season of Castle.


With Beckett still in D.C., Castle and the boys investigate the murder of former child star Charlie Reynolds, who rose to fame playing the lovable nerd on an early 90s High School sitcom. But the case takes a turn for the strange when Agents Beckett and McCord arrive from Washington to take over the investigation, creating competitive tension in the precinct. But why would a washed-up actor's death warrant Federal scrutiny? Whatever the reason, Beckett and McCord aren't telling. Meanwhile, Castle has to contend with a new face at the 12th, NYPD Detective Grant "Sully" Sullivan (Joshua Bitton, "The Pacific").




Main Cast

Guest Cast


Castle: This is a high profile case. And I am willing to let you guys exclusively benefit from my out-of-the-box crime solving mind.
Esposito: And what do you get?
Castle: Escape from the life in the loft.
Perlmutter: Mr. Castle, you’re back, but not by popular demand.
Rachel McCord: Kate, you’re one of the best agents I’ve ever worked with, but I’m here to tell you you’re fired.

Featured Music


  • This episode introduces a new detective in homicide named Grant Sullivan, whose nickname is Sully.
  • This is the last episode that shows Beckett as a federal government agent before being fired at the end of the episode.
  • The fictional show "2 Cool For School" seems to share traits with a number of sitcoms, such as "Saved by the Bell" and "Family Matters". There is even a reference to one of the shows when the CIA agent refers to Esposito as "Mario Lopez" who played A.C. Slater in "Saved by the Bell." The murder victim's role on the show has clear characteristics in common with Screech (SbtB) and Steve Urkel (FM).
  • The "Heat Wave" movie is mentioned for the first time since season 3, "To Love and Die in L.A.", we find out it went straight to DVD.
  • Beckett helps the victim's girlfriend escape from being as a spy for the CIA, which cost her the Department of Justice job.
  • A special feature on the Castle season 6 DVD set includes an audio commentary for this episode from Jon Huertas and Seamus Dever in-character as Esposito and Ryan.