|Till Death Do Us Part|
|Season 4, Episode 11|
|Air date||January 9, 2012|
|Written by||Jeff Bleckner|
|Directed by||David Grae|
When a Lothario is killed, Castle and Beckett suspect that the victim's mysterious double life holds the key to his murder. Their investigation leads to a shocking twist that threatens to disrupt Ryan's wedding with Jenny.
- Nathan Fillion as Richard Castle
- Stana Katic as Detective Kate Beckett
- Jon Huertas as Detective Javier Esposito
- Seamus Dever as Detective Kevin Ryan
- Tamala Jones as Dr. Lanie Parish
- Penny Johnson Jerald as Captain Victoria Gates (credited only)
- Molly Quinn as Alexis Castle
- Susan Sullivan as Martha Rodgers
- Jaime Ray Newman as Holly Franklin
- Sam Hennings as Seth Harris
- Juliana Dever as Jenny Duffy O'Malley
- Mo Mandel as Max Landon
- Desmin Borges as Pablo Barnes
- Jenna Gering as Lisa Hill
- Parisa Fakhri as Colette Roth
- Brian D. Johnson as Ron Hill
- Donald Agnelli as Barry
- Donna Feldman as Jody Garcia
- Timon Kyle as Toby Lang
- Crystal Coney as Judy Doyle
- Tammy Felice as Sexy Woman #1
- Kristina Geddes as Sexy Woman #2
- Byrne Offutt as Manager
- Lindsay LaVanchy as Assistant
- Haley Strode as Hot Young Woman
- Daniel Romer as Cute Young Guy
- Wendy Benson-Landes as Amy Kemp (uncredited)
- Castle: Aah! What are you drinking? Toxic Waste?
- Jenny: We're doing a cleanse. And he forgot his bottle, so I came by to drop it off.
- Ryan: Thanks, sweetie. I love you.
- Jenny: I love you more.
- Ryan: No, that's not possible.
- Ryan (to Esposito, Castle, and Beckett): I know, I know, I know. We're nauseating.
- Beckett: Well it looks like he did the deed before taking the dive.
- Castle: Last item on your bucket list?
- Beckett: What? Why? Castle, if we were getting married would you want to know about all the guys that I’ve slept with?
- Castle: All?
- Beckett: Seriously? You sign women’s chests at book readings. You cannot be shocked that I’m not a virgin.
- Castle: I – it’s just the word –all- suggests a lot. How many are we talking … exactly?
- Beckett: Are you really asking for my number?
- Castle: You show me yours, I’ll show you mine.
- Beckett: Men. You all wanna know, but you don't wanna know.
- Ryan: And do you have to be such a cliché? Stuffing your face with that--that--that thing?
- Esposito: Hey, don't touch my donut. Hey, Ryan--
- Ryan: Don't you eat this! I had enough of you! Don't you--Don't you--
- Castle: Hey, hey, hey! Break it up!
- Beckett: Guys! What the hell is going on?
- Esposito: Talk to hunger strike over here.
- Ryan: He was flaunting that donut.
- Esposito: I was eating it.
- Beckett: Ryan, are you okay?
- Ryan: No, no. I'm fine.
- Ryan: I'll just take these back to my desk.
- Esposito: Sit down, bro.
- Ryan: What? What? Why do you guys look so serious?
- Esposito: You should... eat something.
- Beckett: Yeah, you look hungry. You've got the posture of a feral cat.
- Ryan: Nah. I was telling Jenny about Javi's antics last night... and we got to talking about the case. And she told me she met Bailey at a bar a month or so after we started up.
- Esposito: She told you about that?
- Ryan: Yeah. She had no idea that he was some kind of professional pickup artist.
- Castle: And you're not upset at all?
- Ryan: Hey, um, it's not like we were exclusive.
- "Bolero" by Ravel
- While being interrogated, a suspect tries and fails, to pick up Beckett by complementing her on her eyes. In the pilot Flowers For Your Grave, Castle used a similar line that although it failed, and went over better than the suspect's in this episode.
- Inconsistency: When Beckett is sending Ryan and Esposito to The Magic Bottle to investigate, Castle closes the victim's 'ledger of ladies'. When the camera angle changes to focus on Beckett, the book can be seen to be open and it is closed again when the angle switches back.
- In the 9th episode, Season 1 ("Little Girl Lost") Castle makes fun of Ryan's tie. This episode reveals that it was a gift from Jenny for their two-week anniversary.
- In the ledger, it is revealed that Jenny was a 4.5-star entry. It can also be seen that Jenny has a navel ring in the photo
- This is the second wedding that both Castle and Beckett went to; the first was that of Castle's ex-girlfriend Kyra in "A Rose for Everafter". Except in For Better or Worse, the third wedding is for them.
- When Ryan breaks his juice cleanse, he goes for the Mushu-pork, spring rolls, fried rice, Mongolian beef and spare ribs. In reality, both Seamus and Juliana Dever are long-time vegetarians.
- According to Ryan, he and Jenny didn't become exclusive around the time Jenny was with Bailey until second season's The Mistress Always Spanks Twice. Though, ironically, he stated her as his girlfriend in Little Girl Lost and have been dating for two weeks.
- Watch for: Beckett's reaction to Castle describing his 'date' for the Ryan's wedding.
- Watch for: Castle's reaction at Ryan's wedding to Beckett saying about third wedding might be the charm before going in to be seated for the wedding.
- This is the first episode with a wedding, based on the title.
- Two months after their breakup, Esposito and Lanie made up after Lanie's date was revealed to a friend who was gay and Esposito's his cousin after he heard she was going with someone he thought she had moved on but then told her a great compliment, which in later episodes they would most likely to get back together.