He clambers into an opening where the bricks on a house's foundation have fallen out. The hole is small and Sosuke has to press his arms close to his body in order to fit but it works in throwing off his pursuer.
The Jōnin that was following him peers into the hole with a curse. A full grown man like that can barely get his one arm and head into the hole, let alone his whole upper body to grab at Sosuke.
In the enclosed space, the sound of Sosuke's rasping breaths echo loud enough that the Jōnin can hear it and he speaks into the hole.
"Shit, you're injured aren't you?" he pulls away from the opening and stands up. Sosuke can only see the man's ankles but he can hear his shouts for help loud and clear. This was exactly what he'd wanted to avoid, and he wiggles some of the bricks aside to move deeper into the hole.
Eventually, there's a good-sized group of Leaf shinobi and even an ANBU at the mouth of the hole trying to decide what to do.
"I tracked the kid for a good seven blocks because he reeked so bad of blood that I got suspicious. His breathing sounds funny and I think he's injured," the Jōnin who'd chased him into the hole reports to the other shinobi.
A chūnin with a smaller upper body tries to wiggle into the hole at some point to grab Sosuke. He's still running on the adrenaline from the past few days, though, so he reacts when the man's hand gets too close.
The chūnin lets out a yelp and yanks his arm back out to reveal a bloody wound in his palm where Sosuke has stabbed him with a kunai.
They regroup and the ANBU crouches down to look at Sosuke. He shines a light into the opening to see him better. The ANBU lets out a slow breath and it sounds funny when the porcelain mask muffles it.
"The child is an Uchiha," he determines, extracting his light from the hole and standing up to face the other men.
"Should we use a douton jutsu to get him out?" the chūnin who got stabbed asks.
"No, you idiot! You'd bring the whole house down on top of him!" another says.
"The kid is hurt and scared," the Jōnin who had tracked him says, "He's not going to come out unless it's to someone he's familiar with."
The chūnin not so quietly mutters, "Yeah, well they're all dead. So, now what do we do?"
It's silent for a few minutes before one of the men says, "I have an idea. You all stay here and try to coax him out, I'll be right back."
The chūnin grumbles, "I ain't getting near that hole again."
Another Jōnin crouches down to look into the opening while snapping, "Move aside then."
He's an older man with a funny looking burn on his chin that makes it look like he has a beard. He lowers his voice to a smooth drawl, "Hey, it's okay. No one is going to hurt you. You're safe now."
It doesn't relax Sosuke in the slightest because he doesn't trust any of these men to not hand him over to Danzo the moment the old war hawk asks.
...
The ANBU don't even bother knocking before entering the academy classroom. Iruka lowers the chalk he was writing with and Mizuki stands up from his seat at the teacher's desk.
"Can we help you, ANBU-san?" Iruka asks setting his chalk aside and facing the two masked nin fully.
"Your class is dismissed for the day. You and Mizuki-san are to come with us."
The children burst the tense atmosphere with their plethora of questions. The two teachers manage to settle them down and send them on their way before warily following after the two ANBU.
It isn't until they're jumping across the rooftops that Iruka dares to ask, "What exactly do you need from us?"
"It's a sensitive situation. You are the teachers for Uchiha Sosuke, yes?" The ANBU in the pigeon mask asks.
Mizuki pipes up, "Yes. Does this have something to do with the massacre?"
When they get their destination the ANBU in a frog mask quickly briefs them on the situation, "There is an injured child hiding in an opening under this house. We believe that the child is Uchiha Sosuke. Unfortunately, the child is injured and frightened and we have been unsuccessful in getting him to cooperate. We hoped that a familiar face would encourage him to come out."
Iruka nods and moves to the opening to look in. Sure enough, in the darkness he can make out a small form curled up way in the back; the child's rasping breaths are audible.
"H-hey," Iruka starts, sitting down and reaching a tentative hand in, "It's me, Iruka-sensei."
He lets out a slow breath when two red eyes look up at him, "I know you're scared but I can promise that I will do everything in my power to make sure nothing bad happens to you."
He keeps repeating those words over and over and eventually Sosuke uncurls from his hiding spot and starts to crawl towards Iruka's outstretched hand. When he's within reach, Iruka carefully tugs the boy out and wraps him in a tight hug.
The shinobi around them let out relieved sighs and Sosuke is sobbing into Iruka's shoulder. Now that he's in the open, the shinobi are able to catalog his appearance.
The little boy is in his pajamas and the once baby blue garments are stained dark brown with dried blood. Iruka shifts the boy around and a large gash across his throat becomes exposed and Iruka nearly becomes ill when he realizes that he can feel Sosuke's rasping breath coming from a hole in the upper part of his neck where the blade has sliced all the way down to his windpipe.
"He needs to get to the hospital," Iruka says, meaning to hand the boy over to one of the ANBU present but as soon as he starts to peal Sosuke from his person, the child immediately panics.
"No!" it comes out sounding like Sosuke's gurgling gravel but the word is very clear to Iruka.
"It's best not to stress him out any further," the frog masked ANBU says, "-continue to hold him and we will escort you to the hospital."
Sosuke is too weak to cling to Iruka but the man holds him firmly against his chest, anyways. The trip to the hospital is filled with a tense, somber silence and the occasional rasps of Sosuke's breathing.
One of the ANBU had gone ahead and so when they actually get to the hospital, there is a swarm of nurses and doctors rushing to relieve Iruka of the injured child. They don't get very far, though, before the younger of the Uchiha twins starts wailing in fright.
The boy must be running on pure fear alone because he manages to find the strength to dig his fingers into Iruka's vest desperately. Iruka's arms form a protective cage around him and he grimaces at the panicked shouts of the medics.
Iruka turns them away from the crowd and gently rubs his hand over the kid's blood-matted hair.
"I'm not going to let anything bad happen to you," he promises with quiet murmur. He repeats it several times until he starts to feel Sosuke sag in relief.
The second time the medics go to remove Sosuke from his arms; they do so with promises that Iruka will be right outside waiting for him.
The little boy's eyes flash red in suspicion and he has to be pried from Iruka's vest, but they manage to get him on a gurney.
It's complete chaos the entire time Uchiha Sosuke is in surgery.
Iruka gives a statement of the day's events several times and the perpetually stressed third Hokage makes an appearance at some point.
Iruka scrunches his nose at the man when he walks into the waiting room; Hiruzen has a bad habit of chain smoking when upset.
"We had wondered where his body had gone," the old Hokage grumbles as he looks out the waiting room window.
Iruka is staring at the chipping blood staining his hands and admits, "I've never seen someone so scared before."
Hiruzen glances back at him with a grim expression but doesn't say anything.
...
When Sasuke first wakes up after the massacre, he's told he's the only survivor. While he mourns the thought of his parents and cousins, he's especially distraught over the loss of his twin brother.
Sosuke had been meek and weird at the best of times and their parents had never really paid much attention to him. Sasuke had been deeply protective of the younger boy and hadn't minded the way Sosuke had clinged to him desperately.
The loss of someone who he'd vowed to always protect is incredibly disheartening.
At least, it's that way until he's informed that they'd managed to find his younger brother and that he was in fact alive. They won't let him see him, though, no matter how much Sasuke begs.
He figures out why a few weeks later when his brother is finally removed from the ICU and placed in a standard hospital room.
By this point, Sasuke hasn't been in the hospital and has already returned to the academy. It's quite jarring to see the state Sosuke is in right after school on a sunny Tuesday afternoon.
There's a terrible noise coming from some machine that's hooked up to a tube going through his twin's neck. Sosuke thankfully isn't awake to watch Sasuke have a breakdown at his bedside.
The ANBU stationed at the door of the room give Sasuke a clipped recount of Sosuke's injuries.
His throat had been cut so deep that he was lucky he was alive.
The wound is covered with bandages, so Sasuke can't see how bad it is, but based on the tube the boy is breathing through; he knows it's bad.
...
The removal of the breathing tube in his neck turns out to be painful after the fact, as does the strict health care instructions he receives to ensure he heals well.
"While we've removed your tonsils, you are still incredibly susceptible to illnesses such as strep throat. You'll need to ensure that you are diligent in washing your hands and body frequently and keeping your living area clean."
The medic is cool and clinical in his speech, "You will find speaking to be particularly painful for awhile until the inside of your throat heals fully; try not to speak unless absolutely necessary."
Sasuke, who's sitting beside Sosuke, is furiously writing every word down as if the doctor's word is a gospel. Sasuke had thrown such a fit when he first saw the ugly scar marring Sosuke's throat that the younger of the twins doesn't have the heart to not let Sasuke care for him.
...
The moment he's allowed to stop wearing bandages on his throat, he goes without them. Anything near his neck now feels too tight and invasive. Sosuke knows its just PTSD from having his throat cut open, but he can't shake the fear.
Sasuke visibly grimaces at the sight of his throat when he comes down for breakfast that morning. Sosuke can't even wear the standard high collars that the Uchiha are known for without feeling too tight too much going to die.
So, the scar, that's jagged and grizzly, is clear on display and Sosuke doesn't give a shit about anybody else's comfort if he's being honest.
Sosuke croaks out a greeting to his brother and immediately goes for the freezer for some ice cream to sooth his aching throat. That, and porridge are the only things that don't feel like his throat is being torn to shreds with every bite.
Due to his near completely liquid diet, Sosuke has become gaunt and skeletal that's all the more obvious when he and Sasuke are standing side by side.
The other kids at the academy stare at Sosuke's throat in horrified silence when he walks in that morning.
Iruka flinches terribly at the sight as well, and sends Sosuke an apologetic grimace.
The scar goes nearly all the way around his throat; clearly showing that whoever went to kill him had meant to decapitate him. Sosuke's sure that it's a terrible thing to look at.
Thank god his cousin Shisui had been stupid enough to teach him the shunshin technique.
...
Sasuke knows that his brother had experienced something terrible the night their family was murdered. Sosuke had been clingy before, but now he has full-blown panic attacks if they're separated for too long.
Sasuke doesn't want to ask him why, mostly because he doesn't want to make his little brother relive something so horrifying. He's curious, though, as to why Itachi tried to kill him and also about how he'd managed to escape.
When Sasuke goes to the secret meeting place of the Uchiha in Nakana shrine, he thinks he knows how Sosuke got away. Under the stairs is a tiny gap in the stone that is smeared with blood.
Sosuke must have hidden here for a good while before escaping from the compound.
...
The academy instructors tell Sosuke he doesn't have to spar yet if he doesn't think he's ready. He thinks he is until Inuzuka Kiba makes the mistake of getting too close to his throat in their spar.
Something snaps in Sosuke's head and he blacks out. When he becomes coherent of his surroundings again, he's being dragged off a bloody Kiba, kicking and screaming.
Sasuke tells him that he had gone ballistic and had started hitting Kiba over and over again even though he was already down.
Sosuke is mortified and terrified of what that might mean about himself.
Iruka takes him to the Hokage's office and there's a long discussion about the future progression of Sosuke's training.
He stares down at his bruised knuckles and wonders if this means he'll be a good weapon.
They don't let him do spars with his classmates after that, and instead he has to do all of them with either Mizuki or Iruka. His classmates are afraid of him now.
...
"Do you think I'm crazy?" Sosuke asks Sasuke one night over dinner.
Sasuke's head snaps up and his face pinches into a fierce scowl, "Who called you crazy?"
Sosuke shrugs and he doesn't answer out loud because the both of them know that everyone thinks he's crazy.
"People are scared of things they don't understand," Sasuke says and Sosuke is taken aback by how wise those words are, "You've experienced something that they don't understand; to them you are crazy."
"Not to you, though, right?" Sosuke asks.
Sasuke gives him one of his rare smiles, "Yeah, not to me."