Thanks, Watsonmybae, for the prompt. :)

John shuffled down Baker Street's sidewalk, feeling his eyelids droop with every slight step he took. His head was throbbing, his forearm ached, and most importantly, his stomach growled. He needed some food and a quick nap as soon as possible; his body demanded it. After finally making the trip to the door to 221B, he fumbled with his key and went to insert it into the lock on the door, the promise of some tea and biscuits keeping him from curling up right there on the stoop and resting. Before he could even begin to unlock the door, it was whipped open, Sherlock stepping through it and shutting it as he did so. The detective had a smirk on his face when he bumped into the doctor.

"Fantastic; you're on time," the detective said. "We've got work to do."

John sighed.

"Really? Right now?"

"Yes, of course right now. Why else would I be leaving the flat?" Sherlock asked him, with an even mix of sarcasm and genuine curiosity.

"Could I just have a quick nibble? I haven't had anything since-"

"Yes, breakfast, I know. You'll survive without a pack of crisps for the evening, though, I'm sure. "

"Sherlock…"

As John began to protest further, he was quickly shut up when his flat-mate grabbed him by the arm and dragged him back over to the street, hailing a cab.

"Ah! Christ!" John growled, his companion having jerked his recently injured arm. "Could you not do that?"

Sherlock opened the door to the cab that had, quite conveniently, pulled up in front of them.

"What was that, John?" he asked with an indifferent hum, climbing into the back of the car. "Are you coming?"

The doctor groaned and reluctantly clambered in after his friend, slamming the door behind him.

"I guess I am now."

"Scotland Yard, please," Sherlock commanded the cabbie.

And promptly, the car was steered away from the sidewalk and headed in the direction of the Yard.

John eyed the slight ledge the door provided; a wonderful headrest, he thought. And given the fact that his own head was spinning right now, he was keen on using the ledge to dose off. Just five minutes; that's all his body needed.

He began to speak to Sherlock.

"You know, Sherlock, I think I'm going to-"

"Lestrade has need of us in his office; he's unsure of where to turn next in the case of the murder of that executive and his secretary."

Well, sleep was off the table.

"Okay…" John mumbled. Then it registered with him exactly what the detective had said. "Wait, what? You're still on that case? I thought it was-"

"Lestrade thought it was the girl's husband; not me. Your suggesting otherwise is something that I find rather offensive."

"Right. Sorry." John pinched his nose in hopes of massaging away the feeling of daggers poking about at the back of his eyes. "Look, I hate to sound insensitive in regards to this case, but I could really use-"

"Caffeine. You've had a long day at work."

This was delivered as statement, not a question. And that irked John.

"Yeah, right; that's exactly what it is." The doctor grumbled. "More coffee. Great."

The cab came to a stop and, with a half-hearted 'thanks', Sherlock hopped out, leaving his much shorter and tired friend to scramble after him. The detective had gotten a good few feet away before John finally caught up to him, making the unwise decision of jogging on such an empty stomach. It took quite a bit of strength on John's part to not keel over.

"Okay, I'm going to ask you really nicely to not do that in the future," he told Sherlock.

"Do what?" Sherlock responded, eyes locked on the screen of his phone.

"You know what you did."

The two men walked through the doors of Scotland Yard, being instantly greeted by Detective Inspector Lestrade.

"There you are," the man sighed. He looked at John quizzically. "Hey there, John," he greeted.

"You look surprised to see me," John remarked.

"The inspector is easily caught off guard, John, as is made evident by this case of his." Sherlock gave said inspector a smug smile. "So glad you realised your mistake and called in my professional help."

"You can take that grandiosity and shove it up your arse later," Lestrade huffed. "Just follow me to my office."

And so, Sherlock and John, now being led by Greg Lestrade, walked past a multitude of frowning faces displayed by officers and IT people (obviously displeased at the return of Sherlock) to the inspector's office.

Lestrade sat down in his cushioned chair with an exhalation of breath and John and Sherlock stood in front of the desk to face the man. John teetered a bit, the heat of the room only making his dizziness worse.

"So, I'm officially stumped," Lestrade said. "I mean, the guy obviously died from an allergic reaction to the almonds in his coffee. But why was his secretary pushed from the bloody top-floor window?" He scratched his head. "I'm still trying to make sense of that. And her husband still claims that he wasn't there; he was golfing."

"Was he?" Sherlock rolled his eyes.

"Of course not! We checked!"

"Do you think it is quite possible that the man is trying to cover up the fact that he too was having an affair?"

Greg looked shocked by this proposal.

"What? Why would he do that?"

John, still a bit uneasy, decided to try and distract himself by chiming in.

"Maybe because he's afraid that…" he stopped himself when he began to slur.

"That what, John?" Sherlock urged him, obviously expecting the correct response, judging by the way his eyes lit up.

"…that, um…" John blinked. "That his girl… his girlfriend… person… will be, ah… framed… yeah, framed. Right? Or blamed, I mean?"

"Yes…" Sherlock narrowed his eyes. "Yes, that is what I am led to believe. Are you quite well?" He scrutinised the doctor. "You certainly left this morning having had a good amount of food and rest. Yet you do look fatigued; more-so than you did on our way here."

Lestrade agreed, switching tracks from the case to this matter.

"Yeah, he's right, John; you kind of look a bit pale."

"If I had a penny…" John snorted. "Look, I'm fine; I'm alright. Just… carry on with this whole discussion, yeah?"

"Do you want to sit down?" Lestrade asked, offering his chair.

"Leave it alone, Greg," John insisted.

"Right," Sherlock shook his head, easily doing so himself. "What John said; about the case, of course."

The inspector knitted his brow in thought.

"Yeah, okay, I guess that's possible. But what else have we got to go by besides this guy? No one signed in to meet with Liam at the secretary's desk. That leads me to believe that only someone who was really close to the secretary would be able to get inside the office."

"How on earth is that a sensible conclusion?" Sherlock chided. "There are an unbelievable amount of holes to identify; most notably this: why in God's name would this secretary feel compelled to let the very man who she was cheating on enter her employer's office? The same employer with whom she was having relations with?"

"I mean…" Lestrade bit his lip. "What if she just… I don't know… thought they would talk it out? Or maybe she was hoping the three of them could… you know…?"

"Jesus, Greg," John groaned.

"Well, it's possible!" the inspector protested. "There are lots of twisted sex fiends out there! What about that Irene woman, Sherlock? What if this secretary-"

"This secretary is nothing like Ms. Adler, Lestrade, who I would prefer you avoid mentioning from now on," Sherlock snapped. "Now, I would simply like to inter whatever other input you have to offer before you get too carried away with any more of your 'theories', which all seem to reflect the sexual tension that exists between you and your own wife. Let us consider my hypothesis." Sherlock placed his hands behind his back. "It was the secretary herself. Only she would have known of Liam's intolerance to almonds, and therefore would have easily exploited this weakness; she likely hoped it would have appeared as an accident. This death would have allowed her inheritance of Liam's money and perhaps home. Did you check his will?"

Lestrade didn't respond.

"But… the window?" John interjected. "I mean, didn't she… wasn't she-?"

"Pushed? Perhaps. But keep in mind that there was quite a bit of spilt coffee on the floor; a smooth, linoleum floor. This would prove to be a safety hazard to anyone wearing heeled shoes. My theory is that, due to her rushing about the room to clean up whatever evidence she could, given the desk's close proximity to the windows overlooking the street, Cecilia slipped on a particularly wet patch of floor and, in trying to keep her balance, crashed through the thin glass of the window, subsequently falling to her death."

Lestrade sat for a moment, looking a bit overwhelmed and, quite frankly, defeated.

"That… that does sound a bit more plausible," he admitted, rubbing his stubbly jaw.

"Yeah, nice," John said, closing his eyes for a moment. "That was good."

Sherlock turned his attention once more to his friend.

"John, sit down. I haven't the slightest clue as to why you're in the state that you're in, but it is certainly disconcerting and annoying."

"You're… you dragged me…" John slurred, frustrated that he did so in such a way that his argument was completely unintelligible.

That damned light-headedness was back again.

"Stop…" John muttered to himself.

"What?" Sherlock questioned.

Lestrade stood from his chair, noticing that John really looked like he was going to collapse at any second.

"John?"

John took a deep breath and stood up straight, looking both his friend in the eye.

"Sorry. Fine now," he smiled.

And then he fell to the floor.

Sherlock cried out in alarm, quickly catching his flat-mate by the shoulders and lowering him to the ground.

"John!" he called out, lightly tapping the doctor on the cheek.

Lestrade practically jumped over his own desk before sliding down onto his knees next to the unconscious man.

"Have 999 ready on the phone!" Lestrade shouted through his office door.

"John…" Sherlock muttered, simultaneously taking note of the man's pulse and breathing rate. "Respiratory rate is normal. Pulse is alarmingly slow." He was suddenly overcome with the slightest bit of panic. "Exhaustion? Carbon monoxide?" He turned to the inspector. "That must be it; of course! Evacuate the building!"

Lestrade put a hand on John's shoulder and shot the detective an annoyed look.

"For God's sake, would you calm down? It's not carbon monoxide, you git; you know that."

John began to rouse, and Sherlock was the first to take action.

"John!" he said again, as if the name would speed up the doctor's recovery.

"Hm…?" John muttered. "Shit…"

With the help of both Sherlock and Lestrade, John sat up.

"When did I end up on the floor?"

"Are you ill?" Sherlock inquired, grabbing hold of John's shoulders and shaking them.

"What…?" John shook his head. "I… no. No I'm not. Can you just-"

"Poison? Heat stroke?" Sherlock scowled at Lestrade. "Turn the bloody heat down in here!"

"Sherlock!" both the inspector and John seemed to say in unison.

"What?"

"Relax," John said, struggling in Sherlock's tight grip. "I'm fine. It's all fine."

"Every time you say that the very opposite turns out to be the truth," Sherlock growled.

"Look, if you'll just calm down-"

"How can I? Time is of the-"

"I donated blood today, idiot!" John yelled over him.

Lestrade let out a sigh of relief that ended in a chuckle.

"Good God, mate. You had me thinking the worst."

Sherlock cocked his head at his friend.

"You… you donated…?"

"Blood, yes, Sherlock; my blood. It'd just been a while since I'd last done so, so the whole process was a bit taxing. Especially given the long day I'd had. And I was hoping to grab a bite to eat at home afterwards to keep this from happening, but then you whisked me away to Scotland Yard before I had much of a chance to protest."

Sherlock still stared confusedly at John.

"Why would you donate blood?"

Both Lestrade and John gave the man a look of disbelief.

"How… how is that even a legitimate question?" John asked.

"There are plenty of other people whose blood would have sufficed. Why yours? Haven't you lost enough in your lifetime?"

"What are you on about?" John asked.

"Not to mention the number of lives you save as a doctor already. You give enough of your time and your energy to saving lives. Why give your blood?"

Lestrade intervened.

"Sherlock, mate, it's a standard procedure. All they took was a pint."

"And it will take approximately sixteen weeks for him to regain the pint that was taken from him."

"Sherlock, you're overreacting," John rolled his eyes. "I'm fine. I just need a bit of food and sleep." He awkwardly patted Sherlock's shoulder whilst still being confined in the detective's tight grip. "Lestrade's right."

"I…" Sherlock blinked a bit. "Of course. Yes. I'm… I'm sorry."

John licked his lips.

"Yeah… could you let me go?"

"What was I doing?" Sherlock shook himself out of his frantic state, releasing John.

"Thanks," John grunted, rubbing at his forearm again. "So… do you two want to finish up here while I head home? Or, Sherlock, would you rather I stay here?"

Lestrade helped John stand up, making sure the doctor was steady on his feet before responding.

"You can head back home, John. Get some food in you. Sherlock can stay here and talk things through with me." The inspector grabbed his coat and gestured to the door. "Let me get you a cab."

"I shall do so myself," Sherlock said, opening the office door.

"What? But the case-"

"I assure you that it is the secretary," Sherlock told Lestrade. "Check Liam's will, take another careful look at Cecilia's desk; do what it is the lot of you do."

"But Sherlock, how can we be sure that it was her?"

"In the way I just described." He ushered John out the door. "In my eyes, the case is closed. As is this door in approximately three seconds." He nodded. "Good evening, Inspector."

And, as Sherlock had predicted, the door was closed, leaving behind it a flustered and frustrated Lestrade.

"Sherlock, what the hell?" John whispered at his friend, trying to avoid the stares of the Yarders as they walked in the direction of the exit; John's fainting spell had obviously caused quite a bit of commotion.

"You need a cab," Sherlock said.

"Yeah; me, not you. Why are you tagging along?"

"I need to assure that you arrive home safely."

The two of them finally made it outside into the quickly approaching night, Sherlock holding up a hand to, once again, attract the attention of a cab.

"Wait a minute," John stopped him, grabbing the man's arm and yanking it down. "I want you to tell me what that was all about back there."

"What?"

"That episode of yours. I fainted, and you nearly had a nervous breakdown."

Sherlock took a moment before answering.

"Exactly; you fainted. I was simply confused. Surprised, if you will."

"You were shouting angrily about the fact that I donated some of my blood because, apparently, it's- no pun intended- so bloody precious."

Sherlock sighed.

"It's all a bit of a blur, John. But you're, as you so expertly put it, 'fine'. Let us dwell on the matter no longer."

John tightened his lips.

"Are you really that worried about my safety?"

Sherlock looked at the ground.

"Perhaps."

John smirked slightly.

"You know, as overbearing as it is, it's kind of nice to have you worry."

Sherlock furrowed his brow.

"'Nice'?"

"I mean, I don't know," John shrugged. "Call me a horrible person, but I find it kind of touching. Granted, a bit scary, but touching." He cleared his throat. "Anyway… I won't be going back to donate for a while; I have to give my body a break, after all. So there's no need to worry about that anymore."

Sherlock nodded.

"Good." The detective lifted his hand hesitantly. "Shall I call a cab?"

John sighed.

"Yeah. Go ahead."

And, just as quickly as earlier that evening, a cab came round, the detective and his blogger filing into the backseat to be transported back to Baker Street.