Sherlock stared in disbelief and slight horror at the heart-mark on his left wrist. He had managed thirty two years, 6 months and 12 days without it turning up, so why did it think now was a suitable time to show? The answer, of course, was one John Watson. That was the only variable that had changed in the last few months, which meant he was the reason Sherlock's heart-mark was now throbbing uncomfortably. Sherlock traced his long forefinger over the thin red lines of the perfect love heart shape on the inside of his wrist, eyes filled with disdain. Unwillingly, his mind brought the memory to the forefront of his mind.

"Mummy, why do you have a heart on your arm?"

"Well, do you know how I'm married to daddy?"

"Uh huh"

"Well, when I met your daddy, my heart-mark appeared."

"But what does it mean?"

"All members of the Holmes family have a genetic mutation that causes them to gain a mark in the shape of a love heart when they meet the person they are destined to love forever."

"Oh. But that means daddy should have the heart because he was a Holmes before you."

"Daddy does have the heart, Sherlock. I got the heart because I fell in love with your father. If the person a Holmes is destined to love, falls in love with them, they get a matching mark."

"But why?"

"Think of it like this. A Holmes and their mark are like two halves of the same thing. When they're apart, it's as if there's a jagged edge on each of them. Then, when they're brought together, they just fit so perfectly and there are no cracks where the edges used to be."

"Oh. So it's like you and daddy are soul mates..."

The memory fizzles out and retreats back the darkest part of Sherlocks brain as he recognises the slamming of the front door. Sherlock hastily lowers his sleeve and adopts his 'thinking pose' just as John bursts through into the flat. Sherlock could tell instantly that his flatmate was in a foul mood. He toed his shoes off viciously and stomped his way through to the kitchen, muttering mutinously under his breath. Sherlock began counting:

5

4

3

2

"Do you have any idea how much of a pain in my arse your brother is, Sherlock?"

Sherlock smirked, his facial movements carefully hidden by his steepled hands.

"Pray, do tell" he replied leisurely.

"This is the second time this week he's kidnapped me to talk about your 'best interests' Sherlock." replied John. "Frankly, I've had enough. I'd tell him to fuck off if I thought it'd do any good."

"Mycroft simply enjoys feeling superior as he never gets it when he's around me. Just ask him how his diet is going next time and enjoy the look of disdain on his face."

Sherlock listened to John tottering around in the kitchen, making tea and a jam sandwich. He glanced sideways as John placed a cup of tea on the table next to the sofa where he was currently sprawled. Ah, good old John. Always reliable for a cup of tea. His thoughts wove their way to thinking about the heart-mark currently residing on his left wrist. He flickered his eyes over to the shorter man sitting in his chair. Of course, he had noticed the older man's tanned looks. The way his hair glinted in sunlight, the way his eyes crinkled when he laughed. The way his face lit up when Sherlock deduced and he called him 'brilliant'. He had noticed the way his own heartbeat sped up when John flashed the smile specifically reserved for Sherlock. Obviously he thought John was attractive, who wouldn't? But Love? It couldn't be... love. Sherlock had vowed that he would never let his heart rule his head. Sherlock stopped his thoughts with all the force of and emergency brake on a train. He would not allow himself to think anything about John, other than the normal 'not as idiotic as the rest of the human race'. Sherlock swung his legs off the side of the sofa and sat up, reaching simultaneously for his cup with his left hand. A short coughing fit made him look up at John, the 'you're an idiot' look plastered on his face before he noticed where John was looking. He paled quickly (if it was even possible considering how pale he already was) and quickly withdrew his hand, pulling the cuff over his wrist as he went.

"Sherlock what-"

"Just leave it John" he snapped back, not daring to look at the Doctor.

"Sherlock, don't ignore me" said John. "What's-"

"I said leave it John! It has nothing to do with you" Sherlock winced inwardly at the lie but continued. "I'm going to bed" he finished and stormed off towards his bedroom.

"Sherlock wait" he heard John call before he slammed his door behind him, revelling in the way it made the entire flat quiver. He threw himself down on his bed and lay on his front, hoping against hope that John would forget all about the incident.

A few hours pass in which Sherlock continued to lie on his bed, arm under the pillow, glaring at the wall as if it was somehow the walls fault. A creaking outside his door brings his awareness back to the other person in the flat. John. He feels a pang of guilt when he thinks back to how he reacted earlier. He feels more than hears the door being pushed open.

"Have you calmed down now?" asked John from the doorway. Sherlock merely grunts in reply. In his mind's eye, Sherlock can see John rolling his eyes. A creak indicates John entering the room and Sherlock quickly twists around on the bed.

"John, I don't wish to talk about... What you saw" he said grimacing. "So please just go away." John stood a couple of steps into the room, staring dumbstruck at the man in the bed.

"Is it really that bad that you'd say please to get me to leave you alone?" he asked.

"Yes" came the simple reply as Sherlock folded his legs up and wrapped his long arms around them. John entered the room fully and came towards the bed. Sherlock flinched as he sat on the edge, looking at the detective.

"You know you can tell me anything Sherlock? I'm your friend" Sherlock looked up into the golden eyes of the one he was destined to love and felt a deep longing to make him happy. It didn't matter if John knew about the heart-mark right? He just didn't need to know it was him that was causing it. Sherlock sighed and looked away.

"If I tell you what it is, will you forget about it?" he asked. John said nothing so he took the cue to begin. "Every Holmes family member has a genetic anomaly that causes us to have the heart-mark. A mark on our wrists in the shape if a perfect love heart. It appears when we meet the person we are destined to love forever. It could be anyone. Once we have seen that person, the heart-mark will appear." Sherlock concluded his tale and snuck a glance at the doctor on his bed. He was looking at the detective with a glint of confusion in his eyes.

"So, you're in love?" he asked.

"No!" said Sherlock, wincing at the fastness with which he replied. "I mean, I don't-" he let out an exasperated sigh. "I don't know John. I never planned on my heart-mark showing up so forgive me if I'm a little testy."

"Sorry" said John. "So do you know who the person might be? The one who made it start showing?" Sherlock put his head in his hands and groaned.

"Yes, I think I do."

"What happens if they find out?"

"Nothing happens" snapped Sherlock. "It doesn't hurt them if I love them. It hurts me if I love them and they don't love me. I fucking hate being a Holmes" he growled hatefully.

"What happens if they do love you back?" asked John. Sherlock took a deep breath before answering. John really wasn't going to leave this was he?

"What does it matter John? I can guarantee you the person who made my mark appear will not love me back. Nobody loves me; I'm incapable of being loved"

"Sherlock, what happens?"

"Then they get a matching mark! But like I said, it doesn't matter! They're not going to love me back so there's no point in even talking about it." Sherlock huffed. He lay back down on the bed and turned to face away from John, pulling his pale blue dressing gown tightly around him.

"Sherlock-"

"Leave me alone John. I'm done talking about this." Sherlock felt the bed shift as the soldier became more comfortable.

"I'm not leaving until you let me speak" he said, a softness to his voice that Sherlock had never heard before. He felt a pang of longing in his chest. A longing to twist around, grasp the doctor's head in his hands, lower his lips to John's and-

"Fine" replied Sherlock, kicking himself at the catch he heard in his voice. He heard John take a deep breath.

"Your heart-mark... It's for me isn't it?" Sherlock whipped around, panic in his eyes.

"How can you-" but he was cut off by a small hand over his mouth.

"I know" continued John, "because I have a matching one." and John Watson took his hand away from Sherlocks mouth and rolled up his left arm sleeve. There, bright as the moon on a cloudless night, was the pair of Sherlock's own heart-mark.

Sherlock stared dumbfounded at the mark on John's wrist. Suddenly aware that his mouth was hanging open indignantly, Sherlock's jaw snapped shut.

"When-" Sherlock cut himself off, cringing at the way his voice was shaking. He cleared his throat and tried again. "When did it appear?" he asked, trying but failing to keep the catch out of his voice.

"About a month ago" John replied, his voice barely above a whisper and his eyes fixed on Sherlock's.

"How have you managed to hide this from me for a month?"

John chuckled.

"It's not easy keeping something from the world's most observant man, I can tell you. But I didn't know what it was, so I didn't actively hide. I just didn't roll my sleeves up in front of people."

Sherlock nodded once and John cleared his throat.

"So, um, what do we do now?" Sherlock gave him a quizzical look. "I mean, well, it's pretty obvious I'm irrevocably in love with you Sherlock" he stated, once again showing the mark on his wrist.

"I don't... understand" said Sherlock. "I don't- What could you possibly- I'm not-" Sherlock was cut off as John leant forward and melded their lips together. It was far chaster than Sherlock imagined John's lips softer than they looked, although slightly chapped. Sherlock felt a shiver run through him and his eyes closed as he began to kiss back. He felt the tension leave John and shivered once more as he felt John's hand running up his arm to cup the back of his head. John ran a warm tongue over his bottom lip and Sherlock let out a quiet moan. John pulled softly at a curl at the back of Sherlock's head and he gasped, John taking advantage of his open mouth, immediately delving in and running his tongue against the inside of Sherlocks mouth. Sherlock moved his hands to rest on John's hips. Getting more confident with each passing second, Sherlock moved his own tongue to meet John's, feeling a spark of pleasure pooling in his lower abdomen as he elicited a guttural moan from John. All too soon however, John was pulling away and Sherlock let out a noise of protest. John chuckled quietly and looked into the ever changing bottomless pools of Sherlock's eyes.

"I need you to listen to me, ok?" he said. "No interrupting." Sherlock nodded his compliance and John took a deep breath. "You are the most amazing, brilliant, unique man I have ever met. From the moment you asked 'Afghanistan or Iraq' I knew you were special. You saved my life that day Sherlock. I'd lost all hope in ever being whole again, but then you came waltzing into my life with your coat and cheekbones and gave me a reason to live again. I tried so hard to not let my feelings for you develop into something else, but it was a lost cause the moment you smiled at me. I think I must have loved you from the beginning, I just didn't realise."

John finished talking and folded his arms, his gaze settling anywhere except on Sherlock. Sherlock however, had his eyes fixed firmly on John. A million thoughts at once ran through his head. He had resigned himself to never having John reciprocate, yet here he was in front of him, with physical prove that he loved him. Love. Sherlock remembered that he should feel cold indifference towards that word and the accompanying feeling, but somehow couldn't bring it to the forefront of his mind. Instead, he felt the need to grin when he remembered the words John had said. 'It's pretty obvious I'm irrevocably in love with you'. He didn't grin of course. That would be improbable. However, he couldn't deny the way his skin flushed, or his heart beat faster, or how his palms became sweaty when he looked at his Doctor Watson. He cleared his throat.

"John. As you're aware, this mark only appears when a Holmes meets the person they are destined to love forever. Of course, I had noticed you in ways other than friendship, however I did not realise how deep my feelings for you ran. I found you aesthetically pleasing and extremely, I believe the word is 'fanciable'-" John snorted. "- but until the mark showed I did not know that I could love you. I believed myself incapable of love. I never thought that any feelings I had could be reciprocated as I am obviously unlovable." He paused. "Although, it makes sense it would be you. You are, after all, the only human I willingly tolerate. Alive." John laughed and Sherlock took the opportunity to reach for John's hand. John unwound his arms and stretched out his fingers, intertwining them with Sherlock's own. John smiled sadly at Sherlock.

"You have no idea do you?" he asked. "When I look at you, I don't see the sociopath you claim to be. I see an inspirational, beautiful young man. You do what you do, and you do it perfectly. You say you don't think anyone could love you, but you couldn't be more wrong. I love each and everything about you, and I wouldn't change a damn thing about you. Even if you do leave body parts in the fridge."

Sherlock chuckled and John, smiling, brought their joined hands to his mouth and kissed Sherlock's knuckles. He smirked as a blotch of pink appeared on each of the detectives cheeks. Grinning mischievously, John pulled Sherlock's long forefinger into his mouth and sucked playfully. Sherlock's breathing shallowed as he watched his digit disappear between John's lips, his tongue lightly running over and around the tip. John's cheeks hollowed as he sucked hard, and Sherlock's breathing hitched. He released Sherlock's finger with a soft pop and a wicked grin. He placed his hand on Sherlock's chest, no doubt feeling the beating of his heart through the thin layer of cotton, and pushed him, gently but adamantly into a laying position. John crawled over him and straddled his hips. Sherlock wasn't the blushing virgin people took him for, he had had sex in the past. But most of the time it was for payment for drugs or because he was bored and had nothing to do. He very rarely enjoyed it. But this, this he could do forever. With John. His eyes flickered closed as John lean forward and once again latched their lips together. Prepared this time, Sherlock's tongue met John's half way, instantly tangling together. John's hands ran up Sherlocks chest to his shoulders and pushed down his blue dressing gown. Meanwhile, Sherlock's hands had migrated to grip John's hips, keeping him in place above his crotch. Sherlock felt John nip and his bottom lip and gasped. His cock, which had astonishingly remained at half mast, hardened completely and pushed against John's own stiff length. He groaned into Sherlock's mouth and pulled away, Sherlock following to keep as much contact as possible.

"Oh God, Sherlock" moaned John. "You're so fucking beautiful. You have no idea what I want to do to you.

Sherlock growled and hooked a leg over John's and rolled them over so their roles were reversed.

"I expect it's the same as what I want to do to you" he said, his voice deeper than usual and filled with lust and arousal. He dove for Johns mouth, plunging his tongue into the hot wetness, their tongues dancing together. John's hands began nimbly pulling at Sherlock's shirt, pulling it up and over his head, then removing his own t-shirt in one swift move. One hand remained twisted in Sherlock's curls while the other ran up and down the pale, angular planes of Sherlock's chest. John used his hand in Sherlock's hair to pull him down for another bone melting kiss and Sherlock used this distraction to his advantage and began to undo John's belt. Sherlock ground his hips slightly, eliciting a pleasurable moan from John, which was instantly swallowed by Sherlock. Once the belt was undone, Sherlock tapped John's thigh, urging him to lift. John complied and he was soon rid of the restricting garments, his rock hard prick standing to attention. Sherlock gazed down at him, drinking in every detail and storing it in a room in his mind palace called 'Stuff about John'.

"Well this isn't fair" said John, breathlessly. "You're wearing far too many clothes for this to be equal."

Grinning, Sherlock shucked off his trousers and pants, and kicked them off the end of the bed.

"Better?" he asked.

"Much" came the reply and John swiftly latched his mouth onto the side of Sherlock's neck, sucking hard. Sherlock groaned and tilted his head for better access, feeling a hint of teeth and tongue as John sucked. Feeling Johns grip loosen slightly, Sherlock wriggled down the bed until he was hovering over John's rather erect left nipple, and dove, swirling his tongue around the nub, feeling John arch his back off the bed.

"Fuck me!" came the breathless call as Sherlock nipped at his nipple.

"Yes, I should think so" grinned Sherlock, taking 2 seconds out of his assault on John's chest to reply. He reattached himself to John's right nipple, feeling the ecstasy pulse through him as he arched off the bed once more. He pulled back and carefully wrapped a hand around John's cock and pumped once.

"Fuck! Sherlock! Yes... Hnnng"

Sherlock pumped once more before rubbing his thumb over the glans, smearing the pre-come that had gathered there. John bucked beneath him, cursing and calling Sherlock's name. He leant forward for a quick, filthy kiss, his hand never leaving John's prick, and kissed his way down John's body, before placing a whisper of a kiss on the head of his cock. Before John could react, his aching cock was engulfed in the sweet, wet heat of Sherlock's mouth.

"Fucking Christ! Sherlock, oh yes! Hnnnn"

Sherlock gripped John's hips tight and took as much of him into his mouth as he could, and swallowed. The effect was immediate. John shouted and thrust his hips forward, prompting Sherlock to release him with a soft pop.

"Please Sherlock" whimpered John. "I need you in me, I need to feel you."

"Condoms and lube, in the drawer next to you" said Sherlock, his voice deep with lust and desire. John shook his head.

"No condom. I need to feel ALL of you."

Sherlock moaned, feeling his pulse quicken.

"If you're sure"

"I've been waiting months for this Sherlock, you can be damn sure I'm sure!"

Sherlock chuckled and reached into the drawer for the lube. He squeezed a generous amount onto his fingers and John spread his legs wide. Sherlock stared at the sight beneath him and his breath hitched. It was perfect. He moved his lube slickened fingers to John's entrance and used his long forefinger to circle his hole. The ring of muscle puckered and John let out a sound that was a cross between a gasp and a whimper.

"Please, Sherlock. Please. I need-" John was cut off as Sherlock pushed into John with his finger. He wriggled is digit and John wormed above him, his breath uneven.

"More. Sherlock, I need more. I can take it" he gasped and Sherlock obliged. Working in another finger, Sherlock began scissoring them, working John open. His finger brushed against John's prostate and he arched up off the bed, swearing profusely. Sherlock entered a third finger and felt John grind down onto his hand. He twisted his fingers and thrust into him until John was panting and writhing, begging for more.

"Sherlock, now. Please now" Pulling out his fingers, Sherlock squeezed more lube onto his aching cock and lined himself up to John's entrance. Gripping John's hips, Sherlock slowly pushed until he was buried balls deep in John's arse. He stopped there, relishing in the feel of tight, hot velvet around his prick. John wriggled, trying to get his attention.

"Move, Sherlock!"

Obligingly, Sherlock began to move. Slowly at first, but getting faster with each thrust. John braced his hands on the headboard and met each thrust with his own. Sherlock angled his hips, trying to find that sweet spot and was rewarded with a deep, guttural groan when he hit it. Reaching out, Sherlock took hold of John's swollen cock and pumped, timing each with a deep thrust. With Sherlock hitting his sweet spot every time, it wasn't long until John felt the familiar heat pooling in his abdomen and his balls tightened. With a guttural cry, John came long and hard over Sherlock's hand and his stomach, screaming Sherlock's name. His hole clenching around Sherlock's cock, and seeing the sheer pleasure on his friends face was enough to send Sherlock over and after a few more thrusts, he came in John, riding his orgasm on a wave of bliss. Sherlock collapsed on top of John, breathing heavily and carefully pulled his softening prick out of John. They lay there for minutes, the sticky mess between them cooling and effectively gluing them together. Eventually, Sherlock rolled to the side and picked up a discarded pair of pants and wiped up the mess. Throwing the soiled underwear into a corner, Sherlock lay down facing John, who reached out a hand and caressed his cheek.

"You're perfect Sherlock" he said quietly, "And I really, really love you." He pressed his lips to Sherlock's in a chaste kiss.

"I'm beginning to think I'm not as immune to emotions as I thought, for it seems I love you too" smiled Sherlock. John playfully slapped him on the arm.

"Jerk"

"Hmm, yes but I'm your jerk."

"Yes, you are."

John entwined his fingers with Sherlocks and looked at their matching marks with a soft smile. He closed his eyes and drifted off to sleep with his hand in Sherlock's and the sound of his heartbeat in his ear.