A/N : Here is the second chapter today and so after a standard last chapter here is a little fun because Castle is fun.

Disclaimer : The characters and universe of Castle belongs to Andrew Marlowe, ABC and the Castle writers. This is my attempt at filling the gap between seasons.

As Beckett and Castle leave the interrogation room Beckett comments, "Well that didn't give us much!"

She looks at Castle who has that far away curious look on his face she knows well. It wasn't the look he got when he was going to spin one of his wild theories but the one when there was something in the case had pinged his instinct and was leading to a new and usually productive revelation.

"What?" she asks curiously.

Castle opens his mouth to respond but before he can utter a syllable they are interrupted by a voice behind them.

"Well that was SO interesting, I wish I could bring my students to watch that," says the unmistakeable voice of Castle's mother, Martha.

Beckett and Castle both turn around in surprise to see Martha, dressed in one of her flamboyantly coloured blouses, exit the observation room next to the interrogation room. Behind her, Esposito follows her out of the room, stops, folds his arms and leans against the doorway with a smug look of amusement on his face.

"Mother! You're here! At the Precinct!" exclaims Castle a feeling of dread coming over him at what her presence at the precinct could mean. As Martha walks up to Beckett and Castle, linking an arm with each of them and starts leading them towards Beckett's desk, Castle looks over his shoulder at the grinning Esposito and mouths, "I get you for this". Esposito, smiling even more, holds his hands up in mock protest and follows them so as not to miss the show.

"Yes Richard, of course I'm here," responds Martha with the condescending tone of a mother talking to her dim-witted child.

Beckett, just as equally put off balance by Martha's appearance, closes her eyes and shakes her head before looking at her and stammering, "Uhh..Wh..What are you doing here Martha?"

"Well my dear, I'm here to follow up the offer I made this morning. For you to talk to my class about your interrogations. I could tell you needed some convincing and I knew Richard here would try to talk you out of it," responds Martha, backhanding Castle in the chest. "Believe me Katherine it would mean so much if you could do this. I can't see how it couldn't be anything but a positive experience for everyone and it would make us so much closer. I also thought it would be a good idea for me to see you in action. As luck would have it, when I got here Javier told me you were already in an interrogation and kindly showed me into the viewing room to watch."

They had reached Beckett's desk and Martha releases them both and goes over to look at pictures and the information displayed on the murder board.

"But Mother, surely this could wait? We're in the middle of an investigation!" protests Castle. After all these years it was so rare for his mother to be at the precinct and when she was it was usually an emergency or, in those early days, to bail him out. This is the first time she'd just dropped by and he was feeling his territory invaded slightly.

Martha turns to face him, "Oh pish Richard, I'm not going to interfere. I just wanted to see Katherine's process first hand. I can't just trust your rose coloured observations."

Ryan, who had seen that something good was happening from his desk and didn't want to miss it, rushed over to join them. He stands next to Esposito who is perched on the edge of the desk next to Beckett's. He decides to stoke the fire by enquiring, "What observations?"

Beckett gives her own "DON'T!" look to Ryan as Martha replies, "Oh Richard, goes on about how she's so self-assured, intelligent and cunning in interrogations. How fierce she can be. That she has a sixth sense on just the right attitude to take with a suspect to get them to talk. He says that she's by far and away the best interrogator in the precinct if not the whole NYPD."

Beckett blushes slightly and looks down at this praise while Ryan and Esposito both give Castle a look.

"Oh, Really!" responds Ryan his tone conveying his amusement at Beckett's discomfort and also to Castle as if to say "What are we, chopped liver?"

"Yeah, very interesting," adds Esposito in an identical tone.

Castle seeing this heading down a road that would lead nowhere good tries to respond, "Um mother, what I meant to say was…," but at the look he now gets from Beckett which says "So you didn't mean that?" stops and closes his eyes in frustration at being caught out like this.

Seeing the normally gregarious and confident Castle so easily tied in knots has Ryan and Esposito do a fist bump in triumph. Beckett, to stop it all before the boys have enough ammunition to make their life hell for the next month, makes a rash decision, "OK Martha, I'll talk to your class."

"Oh Katherine, thankyou. It will be wonderful. Now that I've seen you at work first hand I can add my own observations to the discussion. Everyone will get so much out of it," responds Martha smiling wide at Beckett's acceptance.

Castle, trying to salvage some control quickly adds the caveat, "Depending on the case of course. She might not have the time if the investigation is still ongoing."

"We can wait. The class isn't going anywhere. We can fit in to whatever time Katherine has available. Well, now that's settled I must go, I'm going over to Colombia to have lunch with Alexis. See you all later," and with a wave of a hand she sweeps out of the bullpen and to the conveniently waiting elevator.

Once the elevator doors are closed and he is sure she can't hear Castle turns on the grinning boys, "Thanks for your help guys. I thought we were bros?"

Esposito counters in satisfaction, "Hey man if you think we're going to miss an opportunity to put you two love birds on the spot you're sadly mistaken. Watching you two making gooey eyes at each other has gone off the chart since you got engaged. It's embarrassing. It's even worse than how whipped Ryan is with Jenny."

"Dude!" exclaims Ryan.

"Sorry Bro, but we've told you how whipped you are," responds Esposito matter-of-factly.

Beckett, knowing she's probably made a mistake agreeing so readily to Martha and wanting someone to take it out on, advances menacingly on the two boys, "If you think I'm going to forget this you're the ones that are sadly mistaken. And Espo, you're one to talk about whipped, if Lanie walked in here and crooked her little finger you'd be out the door quicker than it takes Ryan to answer a text from Jenny."

"And if either of you think you're getting a loan of the Ferrari any time soon you can forget it," adds Castle for good measure.

Beckett sees movement out of the corner of her eye and looks over at Captain Gate's office. All the banter had obviously attracted Gate's attention because Beckett could see the oft seen look of disapproval over her reading glasses on her face directed at the group in the bullpen. She stands up straight, folds her arms across her chest and in her best business like tone, "Ah, so any word on the video of the van. Was Tori able to identify anyone driving or the plate?"

Seeing Beckett's glance towards Gate's office Ryan and Esposito take the hint and they both move to their desks to reference the files there.

"According to Tori the angle and quality weren't right to see anyone inside but she was able to get the registration. It's a Massachusetts plate registered to a Joe's Plumbing in Fitchburg. It's not reported lost or stolen. I've got a call into the Fitchburg PD to check it out," responds Esposito.

"Massachusetts? How is a plumber's van from Massachusetts involved in this?" asks Castle, joining them.

"Hopefully the Fitchburg PD can find that out for us. Have CSU got anything from Carmody's apartment yet?" asks Beckett.

"They've been able to go through most of the apartment and they've found a few interesting things," replies Ryan holding up a file which Castle takes and starts perusing. "As you saw there was quite a bit of pretty expensive computer hardware and all the hard drives were removed. In fact there was nothing there that held any data, no discs, no flash drives, nothing. On top of that they found a wireless webcam hidden in the ceiling overlooking the front door. Techs think it was linked to the computers in the apartment but without the drives there's no way to know what it saw."

"And I bet it recorded who searched his place," declares Beckett frustrated.

"No bet here," responds Castle his concentration on the file in front of him, "What's this about them finding a key?"

Ryan holds up an evidence bag with a key in it which Beckett takes to examine, "CSU found that hidden in a false brick in the wall of the clothes cupboard in the bedroom. Looks like we were lucky that whoever searched the place didn't find it. It's only got our vic's prints on it."

"Any idea what it's for?" asks Beckett.

"I think so. I went back to Carmody's financials to see if I could find out why he was in Hamilton Heights. I found regular funds transfers to a property rental agency. These were in addition to the payments he made for the rent on the apartment where he lived. I contacted the agency and they gave me an address for an old garage in, guess where?" asks Ryan.

"Hamilton Heights!" replies Castle.

Ryan holds up a post-it with a smile and a nod and Beckett grabs it, "OK, Castle and I will go and check out this place, see if the key matches. Espo, take Sorizo to booking for me and have him charged with obstruction so that we can hold onto him for a bit more and see if he comes up with anything else. Plus his alibi is too weak. Ryan, Sorizo mentioned that Carmody's sister did some work for the Martel agency, can you check that out and with the other modelling agencies whose sites he hacked?"

"Ah, wouldn't you prefer me to make enquiries with a bunch of modelling agencies? I could go down there and conduct some personal interviews," asks Esposito perking up at the possibility of getting to hang around some models.

Beckett gives him one of her patent looks that immediately squashes his hopes, "No Espo, after your recent performance I think I'd prefer a married man dealing with those agencies," Beckett pauses remembering, "Castle, you were going to say something after the interview with Sorizo?"

Castle gets a thoughtful and frustrated look on his face, "I'm not sure. My mother turning up has thrown me out of alignment. I can't remember what, just that something in there didn't seem right."

"You'll get it. Come on let's see if this key is for that garage," says Beckett reassuringly as she moves to her desk for her jacket and keys.