"Did you know the number of possible, unique chess games is far greater than the number of electrons in the universe?" Maura states as she fingers the ivory knight, contemplating her next move as Tommy Rizzoli taps his foot beneath the table. "Also, the folding chess board was originally invented in 1125 by a chess-playing priest. Since the Church forbid priests to play chess, he hid his chess board by making one that looked simply like two books lying together," Maura adds in a thoughtful manner, slightly distracted, instead reaching for her rook.

Tommy smiles politely-more than she can get from Jane when she spouts off her abundant knowledge. Of all people, of course it would be Tommy Rizzoli she finds herself relating to. Dead people and criminals-the two groups Maura feels most comfortable in the company of. Of course, Tommy doesn't quite fall under the latter category. He has an undeniable soft side despite his wrongdoings, and Maura finds him to have a sweet smile.

(Which subsequently reminds her of Jane's.)

"Checkmate." Tommy's bishop gracefully knocks Maura's queen out of place, staring at her king head on. Maura frowns, trying to retrace her previous moves, but her distraction has gotten the best of her. She sighs in defeat, uselessly moving a pawn before Tommy nudges her king off the board.

"You're really not on top of your game tonight, Doc," Tommy states as he pushes all of Maura's captured pieces back in her direction, beginning to set up his side of the board once again.

"I'm just a little distracted tonight," Maura defends, lining up her own pieces. "Because the brain cannot fully focus when multitasking, people take longer to complete tasks and are predisposed to error."

"You must have a lot on your mind then, because the Dr. Isles I know is never one to make mistakes," he playfully flirts. Maura's eyes dart down the chess board, and she can feel the heat rising to her cheeks.

"Jane is on a date," Maura blurts, knowing this simple fact is the reason she can't focus on her favorite board game.

Despite the fact that Maura was the one to encourage the ever stubborn Jane in her flirting, force her into a figure fitting dress in place of her slacks, and fuss over her hair and makeup as Jane cussed like a sailor, Maura can't ignore the pit in her stomach. She can easily identify it as jealousy, but even the scientific mind of Maura Isles can't grasp reason behind this feeling.

(Rather, in a state of denial, she refuses to admit the origin of her envy.)

Tommy scoffs, bringing Maura's attention back to the board game, where Tommy has already taken his first move. "So who's the unlucky bastard?"

Maura opens her mouth to defend Jane, but she recognizes Tommy's sarcastic tone before the words slip from between her lips. "Officer Jackson Cuff. Age twenty-seven. Temporary position down at the station," she tells him, as if reciting from a medical chart.

She's cut off by Tommy's laughter. "Didn't realize Jane was that desperate." He knocks one of Maura's bishops off the board with his knight.

She sighs, frowning at the board, then looking back up at Tommy. "There's nothing wrong with dating younger men," Maura defends, hardly able to focus enough to make a strategic move. "In fact, it-"

She's cut off by the front door slamming, followed by a stream of cursing.

"I'm surprised to see you back so soon, Cougar," Tommy says wryly as Jane enters the kitchen, stumbling in her heels. "Is is past your date's bedtime already?"

"Can it, Tommy," she snaps, kicking off her shoes a dragging a chair up beside the table. "Maura, what else did you tell him?" She runs a hand through her long, dark hair, sounding exasperated.

"Just his name. And age," she adds the obvious. "He was curious," she adds with a shrug.

Tommy focuses his attention back to the board, and Maura carefully watches his move, determined not to let him beat her again. But she is distracted as Jane lets out an irritated huff. A wry smile tugs at Maura's lips, knowing that her lack of interest is making Jane jealous.

(Her stomach always flutters in delight when she realizes Jane becomes jealous as well.)

"Looks like you guys are too busy with your date to ask me how mine went." Maura can imagine Jane shrugging in a nonchalant manner as she mutters the words.

"For the nineteenth time, Tommy and I are not dating," Maura dares to avert her eyes from the board, and in the split second she does, she briefly catches Jane's gaze.

"Sure, sure-wait, you've been counting?" Jane sounds annoyed and exasperated once again.

Tommy chuckles at their banter, knocking Maura's rook off the board with his queen. "Jane, you're making me lose," Maura pretends to whine.

"Oh, sure, lay all the blame on me." Jane scoots her chair up to the board. "Why don't I just speed up the process?" She reaches her hand across the board, flicking Maura's king with her finger, which in turn creates a domino effect as it knocks over a row of pawns.

"Thanks a lot, sis," Tommy huffs, reaching over to fix the damage. Maura bites in a laugh.

"Well, looks as I'm not welcome here. Not that I was really expecting any sympathy from the two of you anyway." Jane reaches for her heels as she begins to pad toward the front door.

"Wait, Jane!" Maura blurts, rising from the table to approach her. "What happened? Was it really that terrible?" Maura's voice takes a genuine note as she reaches for Jane's arm.

"Well wouldn't you like to know?" Jane still puts of her tough exterior. Maura finds Jane's eyes, letting her know that she's ready to assume her role as her best friend. She nods in Tommy's direction, motioning for him to leave. For a moment, he purses his lips. She knows he doesn't want to miss out on a chance to humiliate his older sister, but he respects Maura enough to follow her request.

Jane sighs, plopping back down in her chair as she and Maura head back toward the table. "He told me I was a bad kisser. But seeing how he was basically in high school two years ago, I didn't take it too personally," Jane says with a wave of her hand.

Maura tilts her head. "Well, there-" she cuts herself off, detecting a tone in Jane's words that lets her know she's more bothered than she's letting on.

"What, were you about to agree with him? I don't see you getting any further in your relationships than I do, Dr. Love," Jane immediately retorts, becoming defensive.

"No, no," Maura quickly assures her. "Though there is an art to osculating." She finishes her thought, her eyes darting toward Jane's lips.

"Oh, come on, Maura," Jane huffs, scowling in Maura's direction. "I've kissed plenty of guys in my day. You can't rely on technique-most of it is impulse and chemistry."

"While those are major factors, there is a definite technique," Maura contradicts, uselessly moving a pawn across the chessboard.

Jane does speak for a moment. She looks quite unladylike with her legs uncrossed, her dress riding up her thighs as she sits ungracefully in the chair.

(Her disregard for every piece of etiquette Maura gives her only makes Maura love her all the more.)

"Fine, maybe I am just a little curious about your 'rules.' But not because I am actually a bad kisser or anything," Jane adds with a tiny glower.

Maura smiles, her hair bouncing a little as she excitedly approaches Jane. "First of all, you should've let me put that lipstick on you. It's November, so I'm not surprised you have chapped lips, but its nothing a little gloss can't fix."

"Ouch, so now I have gross lips? Don't you think my ego's been bruised enough for one night?" Jane crosses her arms like an insolent child.

Maura tuts. "Attitude plays a big role in kissing as well. No one wants to kiss you if you're dripping in bitterness." But she finds herself licking her own lips as her eyes once again dart to Jane's.

"Proceed, Dr. Love," Jane waves her on, though the small smile playing at the corner of her mouth lets Maura know she's enjoying this more than she's letting on. "Apparently my love life gravely depends on it."

Maura pulls her chair up next to Jane's, her knee brushing against Jane's, always excited when she has the opportunity to inform.

(She does not admit that engaging in this activity with Jane means so much more than that.)

"Eye contact is important. Making deep eye contact during the approach to a kiss and afterward will create a more intimate bond with your partner," Maura explains, her own eyes finding Jane's.

Jane's about to roll her eyes once again, but as they lock with Maura's, the atmosphere in the room changes considerably. Jane's expression softens, her brown eyes widening ever so slightly, and Maura does not have the will to pull away as a warm smile tugs at her lips.

But after a moment, she coughs, her cheeks a little pink. "Where was I? Oh, yes. After you make that, um, intimate eye contact, it's important to make sure that the kiss is just one fluid action, rather than focusing on the individual aspects, such as what do with your teeth, tongue, head, and hands, which is slightly contradicting, because to attain that perfect motion, you have to be well-versed in how each individual part plays a role in achieving a pleasant kiss." Maura pauses for a breath, catching Jane's eye again.

"Maybe," Jane says slowly, "we should just back up a little and work on that idea of eye contact again."

Maura skims her tongue across her lips again. "Yes, of course. That is a very important aspect in setting the mood of the kiss."

Finding Jane's gaze is all too natural for her. Jane scoots forward in her chair, reaching out to cup Maura's cheek gently. Maura feels her heart pound furiously, her mind swirling with too much emotion for her to analyze the situation. For a moment, she is frightened that she has no grasp on her impulses, but as Jane's breath fans across her face, she realizes she doesn't care.

"One fluid motion, right?" Jane whispers, her thumb stroking Maura's lightly.

Maura closes her eyes as Jane's lips brush against hers, gentle at first, but Maura's hands snake around Jane's neck to pull her closer, her fingers tangling in her hair. Jane parts her lips ever so slightly. Maura sucks gently on her bottom lip, already regretting the moment they will have to surface for air.

"I'm not so bad, am I?" Jane pants, her voice a little husky as she breaks apart, her face still close to Maura's.

Maura can only shake her head. She wants to ask about what just happened. She wants to analyze the unfamiliar feelings coursing through her body. She wants to understand, but for a moment, she lets it all slip away as she leans in to kiss the person she loves most once again.

Jane chuckles against her lips. "Technique is only a small part of it. Chemistry and impulse just make all the text book rules come naturally," Jane mutters. "Admit it, maybe I have something to teach you."

"Oh you shush," Maura pretends to whine. "Or else I may decide I don't want to kiss you anymore."

Jane responds by hungrily capturing Maura's lips.

(Perhaps letting Jane be right more often wouldn't be so bad after all.)