Disclaimer: I own nothing.

Warnings: Mentions of past child abuse; language.

Summary: He's known as "Holmes" to most and "Sherlock" to a select few. But there's one person - and only one - who calls him by his true first name. Paternal!Lestrade.

Notes: Anyone familiar with Holmes scholar William Baring-Gould probably knows where this one is going. Title comes from Ray Bradbury's Martian Chronicles. Further notes at the end to avoid spoilers.

The lights in the bathroom were off, and it took a moment of groping for Lestrade to locate the switch. When they flickered on and he saw where Sherlock had got to, he let out an involuntary hiss.

"Christ, Will," Lestrade muttered. "What've you done to yourself now?"

He dropped his files on the counter-top and strode over to the mess of limbs on the floor, the slap of his shoes echoing in the otherwise-empty bathroom. Sherlock was sprawled across the floor, forehead pressed to the cool (if unsanitary) tile, drawing sharp breaths through his nose. Lestrade crouched in front of him and pressed his fingers to the side of his neck, feeling beneath them the beat of a thready pulse.

"Go...away," Sherlock growled through clenched teeth.

"No," Lestrade said, even though he knew what was coming next. Sherlock despised invasions into his privacy, and nearly always retaliated.

"You're drinking...again," Sherlock said as the fingers pressed into his skin, forced to pause for a gasp of air between his words. Lestrade brushed the heel of his hand across Sherlock's forehead, feeling for a fever - none, as he expected, but that didn't mean much. He recognized this - Sherlock's mind in a frenzy, shoving him back and forth without pause until he was literally paralyzed. It was frightening to witness; he couldn't imagine what it was like to experience.

That, coupled with how he knew Sherlock ran himself to the ground on cases such as the one they had just closed, refusing to eat or sleep - well, it was no wonder the man had collapsed. They had been in his office, coats discarded and shirt sleeves rolled up, going over the final details of the paperwork when Sherlock had gone sickeningly pale and made an excuse to duck out of the room. Lestrade knew it couldn't have been due to the gruesome crime scene photographs; the man had a stomach made of steel.

"Only occasionally," Lestrade replied, and hauled Sherlock into a sitting position from where he'd been slumped over on the floor, supported only by his forearms. He propped him against the wall and peered into his face, taking in the bloodshot eyes and clammy skin. "You'd know if it was getting out of hand; never could hide that from you."

"Started after the - uh - the Larson case," Sherlock wheezed, and Lestrade nodded.

"Were you sick?" he said, forcing the subject away from himself. He allowed Sherlock these invasions on occasion, these moments of deep probing, only because it helped to focus his mind; helped to bring about some sort of order from the chaos.

Sherlock gave an odd jerk of his head. "No."

"So when was the last time you ate?"

"Lestrade -"

"Don't start with me; I'm not in the mood." Lestrade lowered himself to the floor so that he was kneeling rather than crouching, easing the strain on his knees.

"Three days ago," Sherlock said finally. He was starting to get his breath back.

"What about sleep?"

"Same."

"Can you stand?"

"Not just yet." Sherlock leaned his head back against the cool tile wall and pressed his palms to his thighs; Lestrade saw a tremor go through the long fingers.

"Chasing a man for nearly half an hour on foot, while running on no sleep and no food..." he muttered, trailing off. "Well, can't have done you any favors, mate."

"Yes, thank you for that observation, Lestrade," Sherlock muttered acidly.

Lestrade sat with Sherlock for a few moments while he rallied, watching as some color returned to the detective's face, enough so that his skin no longer appeared translucent. A thin sheen of cold sweat had broken out across Sherlock's forehead, and Lestrade pulled out his handkerchief to wipe it away.

Something changed in Sherlock's demeanor at the gesture; the stony mask, having already sustained heavy fire from the sudden spell of weakness, slipped away completely as Lestrade drew the cloth across his forehead. Deep furrows cut into his face and his mouth thinned to the point of disappearing and when his eyes flicked to Lestrade he looked - pained.

Devastated.

Good God, what had happened today? Lestrade schooled his face to remain impassive as he pocketed the handkerchief and pulled himself to his knees again.

"John's at the surgery, I take it?" he ventured calmly, not drawing attention to the fact that Sherlock's expression was as open as he'd ever seen it, and he looked beyond shattered. It was unsettling.

"Flu season," Sherlock offered, and the simple question served its purpose. His mind was focused elsewhere now; back on the present, rather than with whatever had been occupying him. He gathered some of his defenses, and the expression on his face cleared. Lestrade nodded.

"So I gathered. Do you have your flat keys on you? Good, I'll give you a lift home. C'mon."

It took some doing, getting Sherlock to his feet, and to move under his own power he required an arm around his waist. Twenty minutes later, Lestrade was helping him out of his own car and up the seventeen steps to 221B, where he deposited the younger man on the sofa and made for the kitchen.

"What are you doing?" Sherlock's sharp voice called to him.

"Getting you some food," Lestrade said. He eyed the cluttered surfaces and barren cupboards in dismay. "Provided there's anything edible in here, that is."

He wasn't sure that there was, in all honesty, but he scrabbled together the tamest-looking foods he could find and brought them out to Sherlock, hoping that none of them had been part of an experiment. He found that the other man had slipped to the floor, where he was sitting with his legs outstretched and leaning back against the sofa, eyes closed. Lestrade joined him, ignoring the protests in his joints, and handed him the plate.

"Are you dizzy?" he asked.

"Not any longer," Sherlock told him, straightening. He picked up a piece of toast and took a tentative bite.

Lestrade brushed a hand across his brow, feeling for fever once again. "You sure you're all right?"

Sherlock's silence was a beat too long when he answered, "Yes."

"William."

He was careful about using Sherlock's given name. As far as he knew, he was the only person apart from Mycroft who knew it - well, the only person alive, at least. Sherlock's mother had passed not long after he'd met the detective, and as for Sherlock's father...as he understood it, the man hadn't exactly been mourned when he'd passed during Sherlock's first year at university. The precise nature of that animosity was still up for speculation.

Lestrade took it as an immense sign of trust that Sherlock allowed him use of the name now and again - it was something he didn't even allow his own brother to do. And Lestrade was careful, in turn, to use it only when no one else was around. Even then, it was seldom that the name slipped out - only when he was particularly stressed or concerned over Sherlock's welfare. Or particularly furious with the detective.

"What happened today?" he asked finally.

"I - it was nothing."

"Sherlock, please."

He was silent for some moments, and Lestrade didn't press any further. It was useless, he had learned over the years, to push Sherlock too hard - ask too many questions, and Sherlock shut down, pushing out everyone and everything he'd dared to let in in the first place.

"The witness this morning," Sherlock said finally. Lestrade frowned, recalling the seven-year-old boy who had watched his sister's murder. The DI had only caught a glimpse of him, half-hiding behind the legs of his aunt, and hadn't personally spoken with him. He didn't think Sherlock had, either.

"What about him?"

"He -" Sherlock stopped and curled his hands into fists. "He - his father didn't treat him well. Don't."

He must have felt Lestrade tense at the words, hand twitching towards his mobile, and took brief hold of his wrist to stop him.

"He has been out of the man's care for years," Sherlock assured him. "He lives with his aunt, and there's been no contact. I would not have kept this knowledge to myself for the entirety of the day if I wasn't sure of this fact."

"So that's why you've been...out of sorts," Lestrade said, turning over this information in his mind. He didn't know the extent of the malice that the eldest Holmes had felt towards his son, and had never known how much of it - if any - had translated into physical harm. But at that moment, he'd have bet everything he had that Holmes had never directed a kind word - or a gentle touch - towards Sherlock.

"He reminded you of your younger self. You empathized with what he went through - and it brought up some unpleasant memories," Lestrade continued when his statement was met with silence. Sherlock snorted.

"You give me too much credit, Lestrade, as usual. I reacted the way I did for far more selfish reasons." Sherlock sucked a breath through his nose; sharp. "It...simply made me wish that I'd met you fifteen years earlier."

He started worrying a loose thread on his sleeve while Lestrade's heart sputtered in his chest, and then added, "Or - or twenty-five, even, if I'd been given the choice. I...wondered what it would have been like had someone intervened during my childhood, and realized I would never know."

Lestrade felt as though he had caught a vicious blow to the chest, and all the air was forced from his lungs. That was the reason for Sherlock's unexpected reaction in the bathroom. The gesture of wiping the sweat from his brow was a small one, and one Lestrade did without thinking, but it served to remind Sherlock of all he had never experienced.

"Oh, Sher -" And Lestrade couldn't help himself then. He turned and gathered Sherlock into a fierce embrace, arms going around the too-slight figure and holding on tight. Sherlock let the plate clatter to the floor and dug a hand into Lestrade's shirt; Lestrade rested his chin on the soft curls. "That's not selfish, not at all."

Sherlock gave a choked laugh. "Isn't it?"

"No, Will." Lestrade ducked his head, burying his face in Sherlock's hair, breathing in the scent of soap and sweat and ink. Sherlock shuddered in his grip; he rubbed a quick circle over his back and repeated, "You aren't the only one who's wished that, you know."

"You - you aren't serious."

"'Course I am," Lestrade said in a thick voice. "Why would I lie about that?"

"I can't think of any reason for you to be sincere."

"William," Lestrade drew back; Sherlock wouldn't meet his eyes, and stared instead at the table across the room. "You know what? I'd've been proud if you were my own."

Sherlock's head jerked to look at him in surprise, eyes wide. Lestrade gave him a quick smile that the stunned man didn't return and wrapped an arm around his shoulders, adding, "Very proud."

They sat there for some time, talking little, the companionable stretches of silence between them saying more than words ever could. It felt right, having Sherlock tucked up against his side, and Lestrade tried to imagine him ten, fifteen, twenty years younger - all wild curls and ferocious energy and eyes that were older than his years. It was seldom that Sherlock genuinely smiled; he laughed even less. Lestrade wished he could remedy that; wished he'd somehow met the detective years earlier.

He ached for all that he - and Sherlock - would never know.

Eventually there came, from the first floor, the sound of the front door opening and closing. John's familiar tread started to make its way up the stairs, and Lestrade drew Sherlock in for a final embrace. He felt the thank you more than he heard it, rumbling from Sherlock's chest through his own.

"Anytime, Will," he whispered, finally pulling away. Sherlock scrubbed a hand across his face and pulled himself up so he was sitting on the sofa while Lestrade got to his feet, brushing off his trousers and straightening his suit jacket. A moment later, when John stepped over the threshold, Lestrade was gathering his things and Sherlock was reaching for his laptop.

Back to work.

Final Notes: "William Sherlock Scott Holmes" was theorized by William Baring-Gould, in his biography of Sherlock Holmes, to be the detective's true full name. It's not considered canon, but I thought it might be an interesting idea to play with. Feedback always welcome.