|Season 3, Episode 11|
|Air date||January 3, 2011|
|Written by||David Grae|
|Directed by||Jeff Bleckner|
When Castle's novel "Heat Wave" is set to be turned into a movie, actress Natalie Rhodes shows up, at Beckett's invitation, to better understand the character she's going to play. Castle disapproves of her initially, but slowly realizes that she is not as shallow as she appeared to be. Meanwhile, the threesome investigate the murder of a high-class matchmaker.
As the casting for the movie of Castle's Nikki Heat novel proceeds, Castle thinks if the actress auditioning for Nikki Heat's part is deeply unsuitable. He's also a little upset that there have been changes to the script from the original book.
The body of renowned matchmaker Stacey Collins is found. Hours before, Stacey was hosting a party for all of her successful matched clients, so it seems one of them wasn't as happy with their hook-up as she hoped. This case is hitting Ryan a little too close to home because he's planning on proposing to his girlfriend; he just needs to find the right time to do it.
Castle is a little surprised when Natalie Rhodes, the actress set to portray her in the movie, arrives at the crime scene. She wants to really understand the character, so she's following Beckett in the hopes of figuring out what makes the ace detective tick. When Natalie admits than she hasn't even read the original book, Castle gets upset. Ryan finds himself constantly tongue-tied in Natalie's presence, a situation exacerbated, as he informs Esposito, by the fact that she is on his "Freebie Five" list.
During the investigation, Natalie shadows Beckett much like Castle normally does, and studies Beckett's every move, immersing herself in the role, even dressing like Kate and mimicking Beckett's mannerisms. This is shown to start to annoy Beckett, mainly starting when Natalie takes her coffee that Castle always gives her every morning, upsetting her. And because Castle based the character of Nikki's main love interest on himself, Natalie decides that she has to go after him romantically as well. Beckett stumbles upon Castle and Natalie/Nikki passionately kissing in an elevator, obviously shocking her.
Ryan's girlfriend, Jenny, accuses him of spending the previous night with Natalie. Ryan can't tell her the truth about where he went that night: he went to ask Jenny's parents for permission to propose to their daughter. Beckett is roundly upset that Castle locked lips with Natalie/Nikki, but she's appeased when Natalie later tells her that he turned down Natalie's suggested liaison.
Stacey and Greta were conning clients because Stacey felt guilty for matching up these clients with women whom they would leave without a penny. Greta refuses to give Beckett the names of the other clients, but Nikki Heat (Natalie) manages to get Greta to talk. Scott Donner, a client who was caught cheating, killed Stacey after confronting her about some incriminating photos of his infidelity. Donner threatens to kill himself by putting a gun to his head. All seems lost when Natalie as Nikki Heat steps in, giving the performance of a lifetime (while acting out dialogue from the movie script) and manages to talk Donner out of committing suicide.
With the case closed, Natalie decides to leave the team, but she's disappointed that she couldn't get to do more "research" with Nikki's author. Ryan finds the perfect place to propose, at the station, and Jenny says yes.
- 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 (credited only)
- Ruben Santiago-Hudson as Captain Roy Montgomery (credited only)
- Molly Quinn as Alexis Castle
- Susan Sullivan as Martha Rodgers
- Thomas Calabro as Scott Donner
- Stephen Macht as Bill Wellington
- Juliana Dever as Jenny Duffy O'Malley
- Randall Batinkoff as Brad Williams
- Tymberlee Hill as Julie Taylor
- David Parker as Duke Jones
- Laura Prepon as Natalie Rhodes
- Kelly Thiebaud as Chloe Graves
- John L. Curtis as Desk Clerk
- Jon Briddell as Richard Weiss
- René Ashton as Amelia Weiss
- Melody Thomas Scott as Tonya Wellington
- Lenny Citrano as Lead Lawyer
- James Andrew Walsh as Desperate Man
- Juan Alfonso as Delivery Man
- Schae Harrison as Uniform Police Cop
- Monica Staggs as Stacey Collins (uncredited)
- Castle (to Ryan): No, no. You can’t just ask. You gotta make a statement. It’s gotta be big. Helicopter ride…
- Beckett: Actually, most girls prefer something a little more intimate.
- Castle: So he’s just supposed to be boring and ask ‘Will you marry me?’ And helicopter rides are intimate.
- Beckett: Yeah, sure. If you wanna spend the most romantic moment of your life with Reggie The Chopper Pilot.
- Beckett: According to her business card she’s a high end matchmaker.
- Castle: Like millionaire matchmaker.
- Ryan: Without the reality show.
- Castle: Or pulse.
- Ryan: That too.
- Castle: She’s a civilian. Aren’t you afraid she’s gonna get in the way and mess up the case?
- Beckett: You’re kidding, right?
- Castle: Hello, I am your creator.
- Ryan: Jenny! Jenny, wait! Jenny, could you please- Sweetie, could we just talk about this?!
- Jenny (cries, gets in the elevator, and pushes Ryan): I hate you, Kevin Ryan.
- Beckett: If it's so adorable why didn't you sleep with me? Her 'me', not me 'me'.
- Castle: Oh. Well, a fictional character that I wrote, based on you, played by Natalie Rhodes? That’s just...way too meta.
- Ryan: We really should have a code word so we all know which Beckett to kill when her clone army attacks.
- Beckett: Unless we make a pre-emptive strike.
- Ryan: I didn't play darts with Javier last night. I went to go see your parents because I had a question for them. Jennifer Scout Duffy O'Malley... will you make me the happiest guy in the world and marry me?
- Jenny: Oh, my God. Uh, Y-yes. Yes! Yes.
- Ryan: Yes?
- Jenny: Oh, my gosh.
- Castle: That was big.
- Beckett: And intimate.
- "Flower" - Amos Lee
- This is the first episode that neither Lanie Parish nor Sidney Perlmutter appears as the medical examiner. The second episode later would be Headhunters in Season 4.
- Beckett does a literal 'spit take' when asked by Natalie if Castle is gay.
- Natalie Rhodes discusses with Kate the unresolved sexual tension between Castle and Beckett. "He's into you, but you're determined not to give in to these feelings that you clearly have for him." Beckett is horrified by Natalie's dissection of their relationship, but never actually denies it. This is similar to the exchange with Madison Queller in "Food to Die For". But she shows a deniable look to Lanie in A Rose for Everafter
- Natalie states the screenwriter made a lot of changes between the book of Heat Wave and the script, also stating she hadn't read the book - but without having read the book she'd have no way of knowing what changes had been made. As she doesn't enumerate them, however, it may simply be that someone, the scriptwriter or a producer perhaps, told her that there were lots of changes.
- Watch for: Beckett's face when Castle demonstrates a stupid proposal by asking her to marry him with Ryan's ring.
- This marks the second time that Castle had presented Beckett with an engagement ring, the first was in Food to Die For. Although in the episode Watershed, he presented her with the ring differently (her).
- Watch for: Beckett's face when Natalie Rhodes takes the coffee Castle brought for her.
- Castle tells Beckett that he didn't sleep with Natalie because it was "Too meta". However, because he breaks up with Gina in the next episode, we know that he was still in a relationship with Gina at this time, and that's another reason why he wouldn't have slept with Natalie.
- This episode we learn Jenny's full name is Jennifer Scout Duffy O'Malley.
- Ryan stated to Castle that he met Jenny at K.J. McDoogal's, which is a bar.
- This is the first time we see someone propose to their girlfriend.
- It's possible that Jenny is from Flushing. 
- Watch for: Castle's face when Beckett happens to ask him why didn't he slept with Natalie.