Castle starts his day bantering adorably with Alexis and Martha. The scrambling of parent/child roles was fun in this episode. Alexis’s sudden cheerleader ambitions were almost out of character, but desire to diversify for college applications was right in her wheel house.

Once called out to the crime scene, the victim is found scantily clad, hanging by her wrists from monkey bars, covered in caramel sauce. Parrish is able to surmise that the victim was possibly strangled, but was definitely killed elsewhere. That theory is also compounded by Ryan and Esposito finding side by side wheel marks, indicating the victim was probably brought to the scene in rolling luggage. Parrish also chose to share a bit more than she normally does: “I can do the chocolate, I’ll even do the whip cream bikini, but caramel? I prefer slippery to sticky.”

And just as surprising to Castle is Beckett’s rampant knowledge of bondage gear. She’s able to quickly surmise that the leather cuffs on the victim were custom made. Castle is quite intrigued.

Beckett was far more scintillating than usual tonight while dropping comments about knowledge of bondage, positions, and fetish clubs. She claimed her knowledge was from working vice, but it remains to be seen if there is more to Beckett’s insight. (Then again, this is ABC, not Cinemax.)

The case moves along quickly once the victim is identified as Jessica Margolis. Her boyfriend Tyler, a med student, fills in some background details. Jessica had been working on her PhD thesis on sexual bondage and domination. She’d been meeting and interviewing people within the lifestyle and observing sessions.

They next meet her roommate, Danielle, who she had been rooming with since freshman year. She hadn’t seen Jessica, so assumed she was at the university working on her thesis.

At the university, her faculty adviser refers to the office where she kept her notes on Mistress Venom, who she had been shadowing. At the office, the meet her two fellow PhD candidates with whom she had been competing for the same fellowship. Kelly (researching glass ceiling) and Matt (researching AIDS treatments in inner city clinics) were not thrilled to be competing against Jessica “watching some dominatrix dig her stiletto in some guy’s chest.”

The detectives find that Jessica’s notes were detailed. And she compared with the domination/submission, trapped feelings to those in real life. From her cell phone records, they are led on the path to Lady Irina’s House of Pain.

Surprisingly the House of Pain is in a downtown business district in a swanky office building. Or, as Ryan puts it “conveniently located for all your lunchtime spanking needs.”

Beckett books an appointment for her and Castle as a cover to gain entrance to the House of Pain. (Does anyone else have “Jump Around” stuck in their head now?). Arriving at the bondage club, Beckett hilariously takes charge, dominating Castle for effect.

Beckett: “Do you think we could gag him?”
Castle (with a mild whimper): “Remember my safe word is apples.”

Lady Irina turns out to be a former lawyer. She won’t give out any information on her clients, but informs the detectives that Jessica wasn’t studying Mistress Venom, she was Mistress Venom. Castle is transfixed by her and she attributes it to her lipstick shade of Mistress Red. 

One of the other girls who works at the club recalls a young man in scrubs visited Jessica last week and when he left, she was in tears. The detectives assume it was her boyfriend, but his alibi checks out. They delve into her client list/research notes and find one with a fantasy similar to the crime scene.

Alexis catches Castle viewing Mistress Irina’s website:
“Dad, do we need to talk about this?”
“No, this is research for a case. And we need to get you some noisier shoes.”

The client’s comes in for an interview and all are amused by his nickname, Sam I Am. He has an alibi, but his appearance was fantastic just for Castle’s comment during Beckett’s dominating interrogation. “Sam I Am in a box. With a fox. We’re gonna need some popcorn.”

At the dungeon, Esposito and Ryan interview the other dominatrix and find out that Mistress Irina would have been quite angry to find out Jessica had been doing any side work.. Back at the university, Beckett and Castle find out from Kelly that Matt had keys to the office as well. It turns out he was blackmailing her, threatening to expose her double life, so she’d leave the PhD program. She resigned that day, so Matt had no apparent reason to kill her. He’d even returned copies of her research to her apartment.

Back at the apartment, a false lipstick and pillow-saliva lead turns up implicating Lady Irina, but… Castle has an epiphany about the pillow case being clean and the pillow having dried saliva. Remember the comparisons in her research involving trapped feelings? It turns out that her roommate, Danielle, was scared of being left alone when Jessica and Tyler moved in together. They fought and Jessica died. Danielle staged the crime scene based on the thesis notes.

After a first meeting with Ryan’s sweet girlfriend, Castle wonders if Beckett will every bring around her (possibly imaginary) boyfriend. Beckett thinks he’s jealous.