Author's note: I've had a couple of questions about the character Clair. After consulting my resident fanfic expert I've decided to acknowledge recurring Original Characters in the story summary, then a more detailed description as a prefix to the story, as required. I hope that will suffice.

Original Character:

Cookie (aka Cookie Monster); homeless man living in and around Tompkins Square Park. First referred to in "Castling into it"

Clair Winter (nee Willingham); motorcyclist, process server, Castle's current romantic interest. First appears as a murder suspect in "Castles in the air"

Luther; pit-bull terrier, now Clair's dog, but very loyal to Castle. First appears when Castle rescues him in "The Haunted Castle"

In Defense of the Castle

Wednesday morning Castle receives a generous message from Esposito, "Still at DEFCON 1." So he knows that it's not yet safe to visit the precinct, as Beckett is still very angry over Castle's last prank. He's unconcerned. Beckett will soon calm down and welcome him back. In the meantime he has more than enough to do getting his latest novel through the publishing process. It's slow, tedious work, but it pays well.

After dinner, he's back at work in his office when he gets a call on his cell. It takes him a second to recognize the voice, and he says, "Cookie?"

"Yeah, Castle. Yeah. It's me. I found out who that lady is; the one the lady detective was asking about?"

"Who is she?"

"Betty…dunno her last name. Everyone calls her Mom. She usually stays at the Nazareth shelter; 206 East 4th Street. I asked and they haven't seen her for a while. Want me to ask around some more?"

"No, Cookie. Don't do that. I'll take it from here. Thanks."

"Any time, Castle, any time."

Confused, Castle asks, "Cookie, how did you get this number?"

"The King sold me his phone. Yours was the only number in it."

"You've had my number all this time, and you didn't use it?"

"Well, I didn't have anything to say until now."

Smiling, Castle says, "Well, thanks again Cookie. I'll see you around."

"Yeah, see you."

It's after 9pm, so there's probably no one left at homicide. Castle's thumb hesitates over Beckett's name in his cell phonebook, but he decides to give her another night to cool off.

Next morning Castle dares to return to the precinct, carrying coffees as a peace offering. Beckett is there already, of course. But Ryan and Esposito have not yet arrived. She's busy with paperwork and hasn't spotted him, so he has time to scan for warning signs. There doesn't seem to be any smoke coming out of her ears, so he decides on the direct approach and puts a coffee next to her, saying, "Hey, Beckett. Feeling any better?"

Leaning back, with a sigh, she says, "I was."

Ignoring the jibe, Castle says, "I have something that might help." He shows her the note containing the details and says, "The owner of our thigh bone."

The look of delight on her face, at this scrap of information, shows just how little progress has been made on the case. Pausing only long enough to grab her jacket and her coffee, Beckett says, "Let's go."

The homeless shelter is an unprepossessing red brick building. Castle notices that there are air conditioners on less than a quarter of the windows. Immediately inside the front door is a small reception area. The walls are plastered with notices about services available to anyone living rough. In one corner is a cardboard box containing shopping bags full of food. The bored man behind the counter cheers up on seeing Beckett's badge. They're shown into an office where a soft spoken woman named Agnes is sad to hear police asking after one of her regulars. It seems that Beckett and Castle are just in time for the breakfast rush. Agnes points out a few of Betty's closest friends. Once Beckett is satisfied that she's gathered all the information, they head back to the station.

Ryan and Esposito have been going over the toxicology report and Esposito summarizes, "As suspected, Betty had recently ingested alcohol, though that doesn't explain the large dose of ketamine in her bloodstream." He peers at the report before continuing, "Also present were bergamottin, bergapten and bergaptol." Of course, they have no idea what he's talking about, so he explains, "The drug was delivered in an alcoholic drink containing grapefruit juice and the Korean liquor soju."

So Beckett shares what she and Castle discovered, "Betty was fond of Korean burritos."

Ryan asks, "Do we know how many Korean burrito vendors are in that area?"

Beckett answers, "Just five; all food vans or trucks. Uniformed are already rounding them up."

It's a while before the Korean burrito vendor roundup is complete. With five angry businessmen and women in custody, Beckett gets Crime Scene investigators to search the vehicles. One truck interior lights up like a Christmas tree under the luminol test. Further tests confirm that copious amounts of human blood had been improperly cleaned from inside the truck. The old man who owns the truck doesn't speak much English. So Beckett enlists the aid of a Korean-speaking detective, Gimhae Kim, from another precinct, for the interview. It doesn't take long and the detective explains, "He said that business has been tough, with all the competition in Manhattan. And, with beef prices soaring, it somehow made perfect sense to change the menu. I'm not sure he even understands how wrong it is. He's clearly insane. Good news is that there appears to have been only one victim."

Beckett says, "Ok. Thanks Kim. We'd probably better keep this quiet, until the Department of Health decides how they want to proceed."

"You got it. Glad I bring my lunch to work. I wonder how many cops have eaten…anyway, as you say, better keep it quiet."

By the end of the day, all that remains is the paperwork. Feeling a little guilty about how she treated Ryan and Esposito after their participation in Castle's prank, she lets them go home early and says, "I'll see you tomorrow Castle."

After making sure that the guys are out of earshot he says, "So, we're ok?"

Beckett smiles and says, "Yes, Castle. We're ok. It was actually kind of brilliant. How did you persuade the staff at Mr. Broadway to go along with it?"

"I didn't. The delivery truck was a rental. I gave Esposito the keys as we left the station. He only pretended to show the manager a non-existent warrant. Once there, Ryan won the privilege of planting the fake finger. My one concern was that you would let them conduct the search." Smiling, to lessen the blow, he continues, "Thankfully, you're too much of a control freak for that."

Trying not to smile, she says, "I guess that's fair enough." After thinking, she says, "I know that I'm the one who changed the rules, but I think that we'd better not involve anyone else in the future, ok? Or this could get out of hand."

He offers his hand and says, "Deal."

Relieved at his compliance, Beckett shakes his hand and then asks, "So did you go easy on Clair?"

With a grin he says, "Well, I thought of denying her the keys to the Castle." Beckett is again trying not to smile, as he continues, "But that seemed a little too cruel. Instead, she now owns a scary-looking black dog that will never let another man within ten feet of her."

Beckett laughs and says, "Maybe I was the one who got off easy. How on earth did you persuade her to take him?"

"Luther did that. I already knew that she can't resist a guy with a wounded leg. So I just introduced them."

"You're pretty proud of yourself right now, aren't you?"

He shrugs and says, "Well, no plan is perfect. But this week is working out pretty good so far."

Castle is woken just after 6am by the trill of his cellphone. Barely conscious he answers, "Hmm?"

"Castle; it's Beckett." When he doesn't answer, she says, "Castle? You awake?"

Scrubbing his face with one hand, to clear the cobwebs, he says, "Yeah, I'm awake. Crime scene?"

"I'll send you the details. See you there."

"Ok. I can't promise to be of any use until I've had a coffee, but I'll see you soon."

Waking up properly with a reviving shower, Castle heads to Essex St, buying two coffees on the way. After greeting uniformed officers he's momentarily confused to see that the address is a pawn shop. The team is inside, and he hands a grateful Beckett her coffee, before saying, "I thought your message said this is a restaurant?"

Nodding to a rear door, she says, "Restaurant is through there. The pawn shop front is a gimmick. They've only been open a short time. The stock here is for sale and the owners have plans to make it a working pawn shop soon."

Castle can see that Lanie is examining the body of a young, Caucasian male, partly hidden by the counter and asks, "So, what do we know?"

Looking at her notes, Beckett answers, "Victim is Neil Winston. He was on duty behind the counter around midnight. There's usually a doorman here too. But the killer waited until Winston was alone for a few minutes, before making his move." Nodding at an obvious security camera, she continues, "Apparently the plans for a security system haven't yet been implemented either."

Lanie interrupts to say, "Looks like he was shot twice in the torso and once in the head."

Beckett says, "Mozambique?"

Considering, Lanie says, "Could be. I'll have to let you know later. Either way, it wouldn't have taken long."

"Thanks, Lanie. Call me when you've got something."

"Will do."

After Lanie is gone, Castle has his notebook out when he asks, "Mozambique?"

Ryan answers, "A term for two shots to the torso, followed by a close shot to the head. It pretty much ensures that the victim will die, but doesn't take long. So it's popular as an assassination technique."

Castle writes this down and asks, "So this wasn't a robbery?"

Beckett answers, "Doesn't look like it. The cash register wasn't touched." Showing a few pages of paper, she continues, "Inventory list will tell us if any merchandise is missing."

Looking around, at the secondhand guitars on the wall, and the statuette of a black Elvis inside a display case, Castle says, "Doesn't look like there's much of any real value here."

Nodding, Beckett says, "Still, there doesn't appear to be any other reason for killing Mr. Winston." To Ryan and Esposito she says, "Talk to the doorman. There's an outside chance that his absence from the door wasn't an accident. And get statements from everyone else on duty at the time, just in case." Obviously not looking forward to such a tedious task, she says, "I'll go through the inventory."

Beckett begins systematically checking every item in the store, with the corresponding description on the inventory. Within seconds Castle is completely bored. So he amuses himself with trying to guess what year all the trinkets were manufactured. After a couple of minutes he says, "Beckett?"

"Yeah."

Pointing to a small, black chess piece; a knight, he says, "This doesn't belong here."

Already looking for it in on her list, she asks, "How do you know?"

Gesturing around at the room, he says, "It's all retro; nothing after the '70s. But this piece was handcrafted in Italy no earlier than 2005."

Quite prepared to believe him, Beckett is nevertheless skeptical and asks, "How could you possibly know that?"

"It's from a chess set made for the Ferrari corporation. Every piece is carved from wood and covered in the same carbon fiber used for their car bodies." Gesturing to the knight, he says, "You can see that it looks almost exactly like the Prancing Horse Ferrari logo."

Seeing that he's right, Beckett says, "And you have a set?"

"And I have a set. Gina bought it for me the same year I got the Ferrari."

"Do you know where she bought it?"

Taking out his phone, he says, "I'll ask."

Whilst Castle is on the phone to his ex-wife, Beckett prepares to bag the chess piece for later analysis. In the process, she notices some writing on the base of the piece and copies it in her notebook. Despite Castle's on-again/off-again relationship with Gina, he seems to currently be on good terms with her. Without really listening, Beckett can hear that the conversation is relaxed and continues longer than is necessary. She wonders, yet again, how two wives could have insisted on divorcing him, yet choose to remain in his life. Filing that away with all the other questions she'll never ask him, Beckett focuses on her task.

He's soon finished, and says, "Ferrari's New York City showroom; 55th Street and Park Avenue. She said it cost about fifteen hundred dollars…probably more now, I guess. What were you writing down?"

Beckett shows him her notes, Nxe4, and asks, "Mean anything to you?"

"Sure. It's algebraic chess notation for Knight takes pawn on e4."

At the familiar look on Castle's face, Beckett asks, "What are you thinking?"

"That this isn't his first kill. Unless he's terrible at chess, there's just no way the knight would be in a position to take a pawn, before any other pieces are lost." He pauses before adding, "Besides, killing a pawnbroker? That's not very subtle. I think he's been ignored, until now, and decided to make a desperate bid for attention."

Beckett growls her frustration and says, "God, I hate creative killers." She gives the new evidence to a uniformed officer, with instructions to get it to CSU. And then lets Ryan and Esposito know what's happening. After asking them to check on any crimes with similar MOs, she and Castle head to Park Avenue.

With the cooperation of the manager, it doesn't take Beckett long to get the list of everyone who's bought the Ferrari chess set from the store. In fact, it takes much longer to get Castle out of the store. He reluctantly leaves when Beckett threatens to go without him, but only after buying a pair of racing-red, suede Ferrari driving shoes.

Back at Homicide, Esposito explains, "We found two recent, unsolved murders involving chess pieces. Both were in Manhattan, but in different precincts. The first vic, Sarah Pikeman, was shot twice in the body and once in the head on her way home from work. No sign of robbery or sexual assault. The chess piece; a black pawn, was found in her hand."

Ryan adds, "The second murder was only a week ago. It was declared a mugging gone wrong. Because the victim, Gordon Knight, has a history of such crimes, had a handgun in his hand and still had his wallet, and woman's purse on him when he was shot. A black knight chess piece was found in his jacket pocket. The captain's already talked to the investigating officers at the other precincts and everything they have on the crimes is on the way."

Beckett says, "Good work." And then adds, "Sounds like his targets are random, despite the method remaining constant."

Castle says, "Not really. Pikeman is another name for a peasant warrior; the cannon fodder of ancient battles. They're believed to be the inspiration for the pawn chess piece."

Beckett catches on and says, "And Gordon Knight?"

"Exactly."

Chewing her bottom lip and frowning in concentration, Beckett says to Castle, "So we've got: pawn takes pawn, knight takes knight, and knight takes pawn. Could you work out his strategy from that?"

"Maybe. Though I'll need the other chess notations, and the order in which they were played. I think we can assume the killer is following a famous game, because there would be no point replaying one that we've never heard of. So I should be able to track it down online."

"That'd be great, Castle. Thanks." To the guys, she says, "Soon as the files get here, give Castle the info he needs." Handing them the Ferrari customer list, she says, "In the meantime, we've got twenty four suspects. Start tracking them down for questioning. I'll update the captain."

Once that's done, Beckett starts working on a new murder board. The evidence from the earlier murders soon arrives, and she starts filling in the gaps. Taking the information he needs, Castle commandeers Beckett's computer and gets to work. It's not long before he says, "It's either Frank James Marshall vs Theodor von Sheve, played in Monte Carlo in 1902…unlikely. Or Donald Byrne vs Bobby Fischer, played in New York City in 1956. It is still referred to as The Game of the Century, because Byrne was almost a Grand Master, whilst Fischer was a thirteen year old boy. He not only survived for 41 moves, he won. Also, Fischer played black."

Beckett says, "Sounds like our guy. What's his next move?"

Looking at the screen, Castle says, "Nxc3; knight takes pawn. If it turns out to be Kxh7, then I guessed wrong." Unsure about her response, he hesitates before saying, "You know who might be able to help?"

Knowing that he's talking about FBI agent Jordan Shaw, Beckett says, without rancor, "The captain has already notified the FBI."

Just then Ryan says, "We've got the addresses. Split 'em down the middle?"

At Beckett's nod, he hands her twelve names, keeping the rest for himself and Esposito. Before they leave, Beckett reminds them, "Concealed vests; this guy is dangerous." They nod their compliance and head out. Before leaving with their half of the list, Beckett is looking at the chess site on her computer and asks Castle, "Could you write all that algebra out in plain English for me?"

Hitting print, he says, "I can do that on the way, if you don't drive like a maniac."

Even with Castle's assistance as navigator, they've only been to five addresses around Manhattan before dusk. Three people were home, leaving three alibis to be verified. Two were not in. Castle is reading out the next name and address on the list, when he says, "Ugh! I'm an idiot. Pull over, Beckett."

She does so, saying, "What is it?"

"Hang on a second." He hastily scribbles on the list, and then says, "Look!"

Beckett can see that he's chosen one name Cherbet, Rojer Massif, crossed out each letter and beside it has written Robert James Fischer. She looks at him in stunned joy and exclaims, "Bobby Fischer! Castle, you're a genius!"

"I think a genius would have spotted it sooner. But I will be occasionally reminding you of what you just said."

"What's the address?"

"1059 Union St, Brooklyn. But hang on while I check it out." After searching on his phone, he says, "Home of the Fischer family when Bobby was very young. I doubt the killer would be stupid enough to actually be living there. So I guess we're finished for the day."

"Maybe not. You said this guy is trying to get attention. I think he could be near that address, waiting for a sign that someone has discovered his game."

"Stakeout?"

"Except that we have no idea who we're looking for."

After giving it some thought, Castle says, "I got nothing."

Beckett has an idea and makes a few phone calls, the last to Ryan and Esposito, telling them where to meet her. And then she enters the traffic saying, "Mr. Cherbet is the name on the lease of a small property at 835 Franklin St, just around the corner from 1059 Union St. Brooklyn ESU will meet us there."

Once everyone is in place, ESU officers cut the padlocks on the roller doors and enter the building. Not wanting to mess with any forensic evidence that might be there, they only stay long enough to ensure everyone's safety. On the way out, the senior officer says, "Looks like we tripped a remote alarm. It's designed to send an alert to a cell phone, and could have been set up months ago."

Disappointed with this news, Beckett nevertheless thanks them for their efforts. And then she snaps on gloves and enters the building. There's not a lot to see. But one glaring piece of evidence is a milk crate on which rests a chess set. A few pieces are spread over the board.

Beckett hasn't even realized Castle has followed her in until he says, "Checkmate." At her questioning look he says, "White…or in this case, red, is in checkmate, and I think it's the end of the Byrne vs Fischer game."

"So, he's playing with us. He only set this up, so he'd know when we were on to him."

Castle shrugs and says, "Looks like it. And he set it up, so that only someone as smart as you would find him. I don't think we're dealing with someone who's likely to make many mistakes."

"No. But I'll get CSU to go over it anyway." She exits the building to call Crime Scene. Suddenly weary, she says, "Nothing more we can do tonight. Why don't you head back with the guys?"

"That's all right. I'll wait."

End of Chapter One

Another Author's Note: I have a feeling this is going to be a long story. So I've decided to post it as chapters. As always, critiques or questions are welcome.