Joan and Sherlock were lying in Joan's bed after what Sherlock would no doubt later describe as a particularly vigorous evening of sex. Stretched out on his stomach, he was languorously enjoying the feel of Joan curled next to him as she lazily traced the "26.2" tattoo on his shoulder blade with her index finger. The exuberant lovemaking had drained them both, and they were enjoying the middle-of-the-night stillness of the brownstone.

"When did you get this?" she inquired, outlining the number more from memory than by sight, as the imprint was barely perceptible in the darkness of the bedroom.

"I'm not sure. Years ago. After I ran my first marathon, probably," Sherlock murmured, having only recently awoken.

"I can't believe you ever actually ran 26 miles," she said, admiringly.

"Don't forget the .2," he chuckled. That was Sherlock, always precise.

"26.2, then," she corrected herself. "But you don't anymore." She slowly trailed her fingers up and down Sherlock's still-damp back. She felt his muscles lightly twitch under her hand.

"No" was his one-word response.

Even now, after they had been lovers for several months, conversation with Sherlock was a delicate dance. He rarely ever volunteered information. Especially when the topic turned to his past. He was never dishonest, but he usually only answered the specific questions posed to him. Nothing more. It was in part, Joan was sure, just Sherlock's way of maintaining efficiency in all areas of his life. Extraneous or unnecessary conversation was a distraction and a waste of time and energy. But also, Joan suspected, it was a way for Sherlock to protect himself from having his thoughts and feelings eventually used against him. Not that he actually believed that Joan would ever take advantage of his personal disclosures. But habit sometimes overruled personal truths. As a result, in most of their conversations, when she wanted to elicit more information from him, Joan always tried to sound casual, not interrogational or accusatory.

She dipped her toe in the water. "Why did you quit?"

Sherlock had been facing away from her, but he turned his head to look directly at Joan. "I didn't quit. I just stopped," he said matter-of-factly.

"Why?" Joan didn't want to push. But in the darkness, she felt a particular confidence to probe parts of Sherlock that were still hidden from her. She hoped that Sherlock would feel equally secure in revealing these hidden parts to her.

Sherlock gazed into Joan's face, appreciating how the moonlight created silhouettes of her features. Joan could read in his face that he was trying to shape a response. "Did you know anyone at your hospital who smoked?" he finally said.

She furrowed her brow in confusion. "Plenty of people. I guess."

"Most employees' work day consists of a coffee, or smoke, break every two hours, no? That's about as long as most habitual smokers want to go, probably could go, without a cigarette." Sherlock waited for Joan to figure out the analogy.

She thought for a moment. "You couldn't go the time it takes to run a marathon - What is that, about 5 hours? - without getting high." For a moment Joan was frustrated that Sherlock could not have just told her that to begin with, instead of having her figure it out. But she forgave, as she knew she always would, his occasional retreat into indirectness in their personal communication. While seemingly contradictory to his desire for exactness and efficiency in most things, Joan knew that Sherlock, as her former investigative mentor, often found it hard to resist the habit of forcing Joan to come to conclusions, even personal ones, on her own.

Sherlock rotated so that he was resting on his side, repositioning Joan so that they were facing each other. "I could not even run a mile without wanting to get high somewhere along the way. At my worst, I could not leave this flat without feeling the need to do so."

"But you've been clean for over a year now." She paused. "You still don't run."

Again, "No."

She would save the natural next question, Why not?, for later.

"Do you miss it?"

"No." Not that he ever could, but looking into Joan's eyes, Sherlock could not lie to her. Not even about minor things. "Yes. I miss the freedom. The rhythm. The self-sufficiency." He continued, "You run. You must know the feeling I'm talking about."

"I've never run a marathon, though."

"Running is running." While they were talking, Sherlock had begun to casually run his hand through Joan's hair. He reveled in its silkiness as he wrapped a strand around his finger, slightly tugging.

Joan turned her face into Sherlock's hand and kissed his hand. "Says someone who runs marathons to someone who runs less than a quarter of that distance. I like the solitude of running. Just you, good shoes, and a pair of headphones."

"It's a good way to clear your head." Sherlock cupped his hand along the side of Joan's face and rubbed Joan's cheek with his thumb. Maybe it was because of the setting – both of them naked in bed in the middle of the night – but he was enjoying the relaxed conversation they were having. There was an openness to their dialogues immediately after sex – he hated the term "pillow talk" – that he had come to cherish almost as much as the sex itself. While making love and after, there was, perhaps naturally, a physical openness to Joan as well that was remarkable. She was not a weak woman by any stretch. Being on the receiving end of her verbal and physical barbs had proved that to him long ago. But beneath, or alongside, that strength was a willingness to expose herself to others. He saw it in their interactions with the victims of crimes that they were investigating. The way that she would sit next to a person, gently touching her hand to the person's arm or leg, making a much needed human connection. Naturally he saw a different version of this unveiling during their lovemaking. He found her lack of self-consciousness, her willingness to instruct and be instructed, her desire to indulge in her desires, and indulge Sherlock in his, both extraordinary and alluring.

Almost unconsciously, Joan moved her hand against Sherlock's head, trying to maintain her concentration. "I would have thought that you'd be more attracted to the physiological, rather than the psychological, benefits of running. The increase in lung function and blood flow. The runner's high –." Joan stopped abruptly. That was it. Joan was unsure of the connection, but he had quit because of the runner's high.

Sherlock smiled ruefully but appreciatively at Joan's realization. "Good deduction, Watson. While a runner's high is only a crude mimic of the euphoria brought on by heroin, it can suffice when necessary. Even after I became clean, I was not ready to replace an illegal and destructive high with that of a legal one. Especially after I became clean. I would not be able to handle the temptation nor the inevitable disappointment"

"It seems a shame to let drugs continue to strip you of something that you used to enjoy." One of the things that Joan respected most about Sherlock was his self-discipline. His single-mindedness and focus were what made him so successful as a police consultant. But when he felt that he had let someone down – or, as was more the case, when he felt that he had let himself down – no one was harder on himself than he. Sherlock was never what Joan would call self-indulgent, but the levels of deprivation that he could impose on himself were countless.

Joan observed a spark of intensity in his eyes. "I have found other things that I enjoy." Under most circumstances, Sherlock could spend hours talking to Joan. But the length of her body next to his, barely covered by a sheet that he had pulled over them some time in the night, was too tempting an alternative. He could feel his desire for her starting to intensify. He smoothed Joan's hair, then moved his hand down her spine.

"I'm glad." Joan rolled in to kiss Sherlock on the shoulder in appreciation. "But don't you want to get something back that your addiction took from you?"

"My addiction didn't take running away from me. I gave it up. I did that." His hand moved to Joan's waist.

"Not running anymore is the penance for your addiction." It wasn't a question.

"Everything has a cost, Joan."

"You've been clean for nearly two years. Your work with the NYPD, and in your private consulting, has been exceptional. Alfredo has nothing but wonderful things to say about your progress. You're even considering becoming a sponsor yourself. And your personal life couldn't be better," her voice nearly purred as she swiftly kissed him on the mouth. She could still taste herself on his lips from earlier in the night. "I'd say that you've more than compensated for whatever mistakes you made while you were using drugs."

"I am thankful for your defense of me. Truly, I am. But I have a ways to go before I am ready to re-claim other aspects of my old life beyond the investigatory." A quick shadow passed over Sherlock's face. " In the meantime," he said, leaning over and nuzzling underneath Joan's ear with his mouth, "right now I'm more interested in re-claiming one particularly attractive aspect of my new life." Sherlock's mouth slowly made its way down to Joan's clavicle. With his tongue, he repeatedly gently pressed into the hollow above the collarbone.

"Is that so?" Joan almost moaned. She reached out with her left hand to hold the back of Sherlock's head.

"Mmmmhmmm," Sherlock hummed. "But if you're really interested in my getting more exercise, I have a couple of ideas we could explore."

"So no more running?" she said, trying to maintain some level of seriousness. Her resolve was weakening, however, as Sherlock was directing less of his attention towards their conversation and more of it towards her body.

He looked up at her with gratitude. And desire. "Not yet. But perhaps I'll go out with you one day." He had transferred his efforts to her sternum, lightly kissing the hollow between her breasts.

"Just don't expect me to run 26 miles." She hadn't intended to try to persuade Sherlock to start running again. But she was glad to see that his resistance to the prospect was lessening.

"Don't forget the .2," Sherlock murmured against Joan's nipple. "You could get there with training."

"26.2 miles is a long way off." Joan gasped as Sherlock bit the underside of her breast.

Sherlock suddenly grew impatient. "How about we try an activity that has more preferred physiological and psychological benefits?" His hand briefly sought between Joan's legs. "Now," said Sherlock, as he pressed Joan onto her back, "let me show you what the 'Stamina' tattoo on my arm refers to."