Title: An Interesting Puzzle
Spoilers: None
Pairings: None
Summary: Mycroft Holmes has had a very bad day. And now it's up to Sherlock and John to make sure he lives to see a new one.
Author's notes: Some liberties have been taken with medicine and poison, I expect, but I mostly tried to keep things as accurate as possible. Warnings for blood and vomiting, if that's not your thing. Nothing too graphically described, but I'll be on the safe side.

Mycroft Holmes was having a bad day. Well, that was a lie. The majority of the day had been perfectly fine. It was only the last few hours, when he'd been abducted, drugged with an unknown substance and shot while escaping that had been somewhat trying.

He limped down the street, using his umbrella for support and trying to keep himself upright. He had to admire the apathy of Londoners. Only one person had stopped to ask him if he was all right and moved on right away at Mycroft's rather blatant lie that he was fine. He knew he had one of Sherlock's Homeless Network tailing him; not with malicious intent, more as though waiting to see if he needed to step in.

He made it to the nearest street sign and tried to find his position in the city. He calculated various routes to safe places and how likely he was to reach them in his present condition. There was really only one place to go.

He turned the corner and headed for Baker Street.

By the time he arrived at the door to 221b, his vision was blackening around the edges. He pressed all three buttons by the door and waited, finding the door getting closer and closer as he swayed towards it. Just as he was about to go face first into it, it opened and a figure was lit up in silhouette.

"I apologize," Mycroft said to it. "I believe I'm about to fall on you."

Mycroft was aware of the fact that he was slipping in and out of consciousness and made a firm decision to stop. He forced his eyes to clear and focused on his surroundings. He was in the flat now, near the stairs on the lower level. He was on the floor. Dr John Watson hovered above him.

There was a dull throb of pain in his shoulder. He moved his eyes down and saw a spread of blood on his shirt and John's hands pressing down with a handkerchief, also stained red.

"I just got this tailored," Mycroft murmured, sadly.

"Yes, it must be very expensive letting your clothes out so often," Sherlock's voice taunted, from nearby.

Mycroft's head was too fuzzy to think of a good comeback just at the minute. He settled on a glare in the voice's general direction, then turned his attention back to John. "Prognosis?"

"Gunshot wound's not too bad," John said. "It's a through and through – lots of blood, but nothing vital hit. I'm more worried about what they gave you."

Mycroft assumed he must have told someone about the situation, but he couldn't remember doing so.

"Shot and poisoned," Sherlock said. "My my, brother, someone clearly wanted you very dead."

"I don't believe my getting shot was part of the plan," Mycroft said. "I was injured in my escape. The intended scheme seemed to be of the 'slow and painful death' sort. Or at least that's what I was told when I was injected."

"How unoriginal," Sherlock said.

"My thoughts exactly, but most people are these days," Mycroft agreed.

"If you two are done being irreverent, I need to get my supplies," John said, sounding annoyed. "G'is a hand, Sherlock. Put pressure on the wound."

Sherlock appeared in Mycroft's field of vision, crouching down next to John. There was extra weight on his shoulder, which hurt somewhere in the back of his brain, and then some of it was lifted. John disappeared, his footsteps sounding on the stairs.

Sherlock lifted his mobile to his ear and began to speak into it. "It's me. I want you on standby. I don't know yet. Just prepare everything you have. Of course I'll pay, I always do. When I call, I want you at the usual spot within two minutes. If you don't answer your phone or if you are late, I will bring your whole operation to the police, is that understood? Good." He pressed a button on the phone and ended the call.

"I thought I had all your suppliers of illicit substances arrested," Mycroft said.

"As if you could find them all," Sherlock scoffed. "Besides, none of this person's substances are strictly illicit. He deals in herbal remedies, which may or may not include poisons and antidotes. Once I find out what they've given you, I want to make sure I can get what I need to reverse the effects. At least, I presume that's why you came to me?"

"Actually, you were simply the nearest place of safety I could think of in my present condition," Mycroft said. "I hadn't thought much farther ahead than getting off the street."

Sherlock looked vaguely insulted. John came back down the stairs, his arms loaded with various medical supplies.

"I wish you'd let me call an ambulance," he said, as he knelt down beside Mycroft. "We're not exactly in the best surroundings here. I'll do what I can."

"It's best to handle this problem in-house," Mycroft said. "And I think your front hallway might be better than your typical NHS hospital. Besides, you once performed surgery in the back of an army jeep while under heavily artillery fire. I doubt this will tax your abilities anymore than that did."

"How could you possibly know about that?" John said. He pulled on surgical gloves, then retrieved a pair of bandage scissors and set to work on Mycroft's shirt.

"I've read your files," Mycroft said.

"Really, Mycroft, you've been after me for years to get myself a friend and I finally make one and you spend all your time pulling his files and abducting him," Sherlock complained. "Heaven knows what you'd do if I got one of those romantic partners everyone is so keen on."

"Die of shock, I suspect," Mycroft said.

"At last, a suitable incentive," Sherlock said. "Though we might not have to wait that long at this rate."

"Do you two ever shut up?" John complained. "Sherlock, help me sit him up so I can clean this out and bandage it."

The pain this caused was acute and Mycroft searched for something to keep his mind clear. He focused on the black bag John had brought downstairs, trying to observe like his brother was fond of doing.

It was in the style of an old doctor's bag – a Gladstone. It seemed to hold medical supplies; perhaps it was a First Aid kit. It was old and slightly beaten up, but otherwise kept in very good condition. It clearly had some sentimental value. There was a silver clasp at the top, engraved with 'JHW' on it. Probably a gift of some sort. The fact it was so well cared for suggested that whoever had given the gift was no longer in the doctor's life.

This was as far as Mycroft got before he was laid back down on the floor, his shoulder wrapped so tight in bandages that he couldn't move his arm.

"You're lucky Mrs Hudson is away," John said. "She'd been in a strop over her carpets."

"I'll pay for their replacement," Mycroft murmured He wondered if he was actually starting to slur his words, or if he was just hearing them that way. Perhaps both.

"I need blood," Sherlock said.

"I believed I've donated enough," Mycroft said.

"I can take it myself," Sherlock continued, ignoring his brother. "I know how to find a vein."

"I bet you do," John muttered. He reached for his black bag and pulled out a syringe and tourniquet. "I'll do it." There was a tight sensation around Mycroft's arm and fingers probing for a vein. Then an alcohol swab and a pinch. "Do you two have the same blood type?"

"Yes," both brothers said, together.

"I might be able to do a direct blood transfusion if it comes to that," John said, thoughtfully. "Though I'm positive Sherlock is anemic, so it might not be the best plan. I don't need both Holmes' on the carpet. Holmeses?" There was another pinch as the syringe was removed. "There's your blood, Sherlock."

Sherlock looked pleased and ran upstairs with the syringe in hand.

"I have a couple of bags of saline. I'm going to put an IV in. It'll help replace the blood you've lost," John said. He stood up and removed a painting that hung on the wall, hanging a bag of fluid from the hook there.

"You're awfully well supplied, doctor," Mycroft noted, as John began to attach the tubing to the IV.

"I've been hoarding a little. Living with Sherlock, you expect to be performing surgery on the kitchen table one day," John said. "I still think you should be a proper hospital, though. I can treat you here, but that doesn't mean I should."

"No," Mycroft said, firmly.

John sighed. "You two are exactly alike," he muttered. "Make a fist a few times." Mycroft obeyed. John's fingers felt for a vein again. Within a minute, there was an IV up and running. "I'll be right back."

The doctor disappeared into 221a and returned a few moments later with a pillow and blanket.

"I'm positively spoiled here," Mycroft said, as the pillow was put under his head and the blanket over his body.

"I guess we're going to be here for a while," John said. "You might as well be comfortable. Do you need anything else?"

"A very large brandy would be excellent," Mycroft said.

John grinned. "I'll ring for the footman," he said. "In the meantime, I'm going to take your blood pressure." He slung his stethoscope around his neck and wrapped the blood pressure cuff around Mycroft's arm. "Any idea what sort of symptoms we're looking at?"

"No, I'm afraid no information pamphlet was offered," Mycroft said. "I don't imagine it will be very pleasant, however. I apologize in advance for anything undignified I might do."

"I won't hold it against you," John promised. He put the stethoscope ends in his ears. Mycroft winced as the cuff tightened around his arm. It deflated a few moments later. "Not too bad. A bit on the low side."

"I've been repeatedly informed by my doctor that my blood pressure is too high," Mycroft said. "Perhaps I have some wiggle room."

John's mobile beeped. He ignored it, but it beeped again.

"He's texting you from upstairs, isn't he?" Mycroft asked.

"Yeah," John said, taking a look at the messages. "He wants to know what colour the substance was."

"I didn't get a good look," Mycroft said.

John tapped at the phone. It beeped again. "He says you're useless."

Mycroft rolled his eyes.

"Any idea who did this to you?" John asked. He put his fingers to Mycroft's neck for a few moments, eying his watch. Then he nodded to himself and sat down in the chair next to the stairs.

"Several," Mycroft said. "But none of them concrete. They favoured the clichéd balaclava'd minions technique."

"How did you escape?"

"Oh, it wasn't too hard," Mycroft said. He was feeling a bit surreal now and was thankful for the questions to keep his mind focused. "Sherlock's not the only one who has trained in escapology."

"You two both act like you were raised by Batman," John said.

Mycroft chuckled. "Merely a mother who was far to indulgent to her children's varied interests," he said. "I did the old trick of tensing my muscles while being tied up, I'm sure they taught you that in the army in case of enemy capture?" John nodded. "That gave me some leeway and they made the mistake of leaving my umbrella in the room. Once I had that, it was all quite simple. Unfortunately, one of the men got a shot in before I was free of the building. Fortunately, his aim was poor."

"What's in that umbrella?" John asked.

"This and that," Mycroft said. "It's very useful."

"Apparently," John said. John's mobile beeped again. "He wants to know if your pupils are dilat – " the phone beeping again interrupted him. "– ed, for God's sake, I have to check them before I can answer, Sherlock." He retrieved a penlight torch from his bag and flashed it a few times in Mycroft's eyes.

"What's the verdict?" Mycroft asked, as John tapped keys amidst yet another beep.

"A bit dilated, but responsive to light," John said. "You feeling any other effects, yet?"

"I'm feeling rather warm," Mycroft said. He'd begun to sweat.

John removed the blanket from him.

Ten minutes later, he had to put it back on as Mycroft become suddenly very cold. Then, ten minutes after that, his heart started to pound in bursts. Then the world got a bit too hazy to keep focused on, and Mycroft fell into a light sleep.

The next few hours weren't too bad, all things considered. He felt wretched and new and unpleasant symptoms popped up and faded away. The poison seemed to work in a slow waves and Mycroft couldn't decide whether that was better or not. On the one hand, he got the occasional reprieve. On the other hand, any reprieve just left him waiting for the next round to hit.

He dozed lightly on and off, mostly during the breaks. John kept a close eye on him, adjusting the flow rate of the IV, monitoring his pulse and blood pressure, giving Sherlock regular updates via text. He had excellent bedside manner and kept Mycroft fairly calm, keeping his worry well-hidden, though not quite well enough to completely convince his eagle-eyed patient.

Mycroft woke up at one point to find him scribbling in a notebook.

"I'm charting," he said, sounding a bit confused at himself. "I don't know why, but I am. Force of habit I suppose."

"And what is the chart showing?" Mycroft asked. He was finding it harder and harder to from coherent words, but John always seemed to understand his slurred speech.

"We're okay still," John said. "Sherlock thinks he's identified one of the compounds. He thinks there were a few mixed together. He's getting closer."

Mycroft felt some hope at this.

Until the vomiting started.

The nausea came on so suddenly that Mycroft didn't even have time to warn John that it was happening. Fortunately, John seemed to recognize a patient about to be sick and was ready, turning Mycroft so he didn't choke and holding a bowl for him to vomit into. And vomit into. And vomit into.

It was vicious cycle, as every time he vomited, it would jar his shoulder, causing pain that made him more nauseated. He couldn't seem to stop and would have been extremely embarrassed if he'd been able to think coherently enough. John dealt with the situation without any sign of alarm, which helped quite a bit.

"I'm going to give you an anti-emetic," he told him, after the vomiting had gone on for far, far too long. "I'm reluctant to introduce anything new to your system, but you can't go on like this."

Mycroft agreed.

John added something to the IV that burned as it went into Mycroft's arm and soon the nausea ebbed away. Mycroft was able to lie back and rest in fits and starts again.

Halfway through the night, he started to hallucinate.

Mostly mundane things at first. The birds on the wallpaper moving. The stairs curving in odd shapes. Flowers growing from the ceiling. Then they got a little more elaborate.

"You okay?" John asked, at one point.

"I am aware that you cannot possibly be holding a hedgehog, yet my brain appears to disagree," Mycroft told him.

John frowned and scribbled something on his makeshift chart. The hedgehog scurried away.

After awhile it became hard to tell whether he was hallucinating or merely having bizarre dreams. He managed, despite the haze, to figure out that most of the hallucinations took place within the confines of 221b, while the dreams took place wherever they damn well pleased.

He had several conversations with Sherlock. Which wasn't entirely unusual, except for the fact that he was Sherlock at aged three – the way Mycroft remembered him. Then he was about ten. Then he was in his twenties, just before he got so badly into drugs. Then he was ten again and speaking in French with their grandmother, who had been dead for fifteen years.

"Tais-toi et ne bouge pas," the real Sherlock said, somewhere in the midst of all these phantasms. There was the sharp stab of more blood being taken. "You're opening up your wound and I have to come down here to help John fix it. It's very annoying when I'm trying to work."

Definitely the real Sherlock.

At some point, Mycroft became too exhausted to hallucinate or dream. He just fell into a big black hole of pure unconsciousness, interrupted regularly when John woke him to check his vitals. It became harder and harder to wake up, to remain lucid, to keep going, to not give in. Only his strong stubborn streak and his faith in his brother's abilities kept him from giving up and letting the poison take control.

Then Sherlock came pounding down the stairs, coat flying behind him. "Don't die!" he commanded, pointing at Mycroft sternly. "If you die before I figure out if I was right, I'll kill you."

Mycroft didn't have the energy to point out the logic flaw in that statement. He didn't have the energy for much, actually. Even breathing seemed like far too much effort. John was trying to talk to him, but he couldn't find a voice to answer back. He just fell into the black again, unable to respond to John's shaking and poking. He didn't even flinch when, several minutes later, another needle was forced into his arm.

He woke up to find the sun streaming in from somewhere, lighting up the hallway at 221b. He also found he was alive, which he was surprised by. He was alive and very, very sore. Not just from the gunshot wound, but every single muscle in his body felt like it had been through an extensive work out. He also had a foul taste in his mouth.

"I'm not dead," he murmured, just to state the fact out loud. He was relieved to find his speech was clear and precise, though his voice was hoarse.

"Obviously," Sherlock said. He was sitting in the chair, knees drawn up to his chest and his laptop on the little table next to him. No, John's laptop. "Otherwise your definition of the afterlife is very unimaginative."

Mycroft ignored him in favour of getting his bearings. He noticed John, curled up in a ball in the floor in front of the stairs. He was asleep, with his head resting on his bunched up jumper. A blanket had been thrown over him by a person who clearly had no idea how to put a blanket over someone.

"Did I break the good doctor?" Mycroft asked.

"He's fine. I think he enjoyed himself," Sherlock said. "Just like old times. What's the word for that?"

"Nostalgia," Mycroft said.

"That's it," Sherlock agreed.

"Tell him to send me a bill for his services," Mycroft said.

He continued his examination. A new bag of IV fluid had been hung up, now a quarter empty.

"John says you aren't allowed eat yet," Sherlock said. "I know that must be a terrible blow for you."

Mycroft made a face. "I have no desire for food," he said.

"There's a first."

"Perhaps I'm turning into you," Mycroft said. "I don't think I can pull off the anorexic teenage girl look quite so well, though."

Sherlock scowled at the computer screen and Mycroft was pleased that he had regained his ability to form comebacks, even if they weren't his strongest.

"How badly was I raving?" he asked.

Sherlock shrugged. "I wasn't here for most of it. John says a lot of it was gibberish. I did catch something about the American ambassador and his houseboy, however."

Mycroft jolted at this. "WHAT?" he said, loud enough to cause John to stir and snort in his sleep, before settling back down.

"I knew it!" Sherlock said, triumphantly.

"Oh for God's..." Mycroft muttered, ashamed for falling for such an obvious trick. "You wouldn't have got away with that were I not somewhat indisposed."

Sherlock just looked smug.

Mycroft put his mind to what sort of loose ends he would have to take care of. There would be finding the culprits, of course. He might be able to convince Sherlock to look into that, depending on how bored his brother was feeling. He had a meeting with someone today, he couldn't remember who. That would most likely have to be canceled or at least moved to a later time. His assistant would need to get take of that. What name was she going by today? He should probably let her know the situation before the emergency protocols started. He had to be missing for twelve hours without contact for that. He guessed he was coming close. He wished he had his mobile, but that had been taken when he was abducted. Not important, it would self-destruct if tampered with or the wrong password entered too many times. Maybe he could -

"Well?" Sherlock burst out, interrupting his stream of consciousness.

Mycroft shifted his eyes over to him. "Well what?" he asked.

Sherlock threw his hands up in the air. "Aren't you going to ask me what they gave you? How I figured it out? What I did to counteract the effects?" he demanded. "Aren't you curious?"

"Immensely," Mycroft said. "But I really do not have the energy for one of your enthusiastic monologues just at the moment. You can be very clever at me later, all right?" Sherlock pouted, making Mycroft chuckle. Which made his whole body ache. "I should thank you, however. You saved my life. I appreciate it."

"Mummy would never let me hear the end of it if I let you die," Sherlock said, dismissively. "Besides, it was an interesting puzzle."

"I'm pleased to entertain," Mycroft said.

"I've notified Mr. Silver of the situation," Sherlock said. "He said he's at your disposal when you're ready to leave here."

"Thank you," Mycroft said. He made an attempt to sit up and failed after about an inch of movement. "...I may be here for some time."

Sherlock grinned. "Well then, you have plenty of time to listen to one of my 'enthusiastic monologues'."

Mycroft groaned and settled back against the pillow, resigned. "Very well. Go ahead."

"Well, obviously, I could start by eliminating several substances based on the fact that you were still alive when you arrived here..."

His brother's voice rambled on, full of delight. Mycroft honestly did his best to listen, but soon found himself drifting off to sleep.

He didn't think Sherlock noticed.