Disclaimer: I play in this universe at times, but I don't own anything you recognise.
Chapter 1: A rude awakening
When Itachi woke up, he was chained to a wall.
This confused Itachi.
Less because he was chained to a wall (although that was not exactly something Itachi had much experience with, funny thing, being extremely good at being a ninja tended to limit one's experience with being detained) and more because he had woken up.
The last thing he remembered before waking up had been Sasuke's face, feeling himself succumb to chakra exhaustion and the disease that had been slowly eating him away for years. He remembered asking his little brother to forgive him.
He also remembered being somewhat disappointed that he was literally going to drop dead from a terminal illness rather than going out the way he had wanted, with Sasuke gaining them both some closure by killing the man who had killed their parents, but really, maybe it was better this way. At least he had managed to do his foolish little brother one last favour by saving him from the Orochimaru parasite that he had managed to pick up in his quest to become more powerful.
The problem, however, Itachi mused to himself as he tested the give of the manacles around his wrists, was that he had been pretty reasonably sure that that was his last act. After all, he had been in extreme chakra deprivation, he had been coughing up blood, blood had been coming out of his eyesockets around his sharingan, oh, and that electrical attack… Kirin, it seemed that Sasuke and he shared a taste for grandiose names for their original jutsu… catching the edge of that had not been fun either.
So Itachi felt that he had pretty good reason to assume that he should be dead.
Oddly, he actually felt comparatively pretty good.
Sure, he was chained to a wall. That was… annoying.
But otherwise? He could see more clearly than he had been able to for ages. He was hungry, thirsty, and felt like someone had been using him as a punching bag recently, and was a little low on chakra… but compared to how he should be feeling? How he had been feeling for the last couple of months?
This was highly suspicious.
Itachi eyeballed his manacles, and decided that he could probably slip out of them if he dislocated both of his thumbs. That would be irritating, as it would limit him in the number of jutsu he could do, but Itachi thought that so long as he managed to not run into any S-ranked nin he would probably be fine to get out of here.
Wherever the hell "here" was…
No matter. Itachi might not be overly used to being chained to walls specifically, but exfiltrating unfamiliar dungeons made him nostalgic for back in the old days when he had been ANBU. Amazing what one could find nostalgic in retrospect. Itachi supposed that it said nothing good about his life that some of his happiest moments as a child had been when he had been sneaking out of enemy strongholds full of people who would more than happily torture and kill him and pluck out his eyes...
Itachi was just about to proceed with his plan of dislocating his thumbs when he heard a noise outside the cell door.
The door opened, and a rather large shinobi wearing a Sound hitaiate walked in.
"Awake, are you? Tougher than I thought you were, Konoha, I thought for sure after that last session that you'd had it for good."
He sneered at Itachi, and pressed a lever, that caused whatever mechanism that was holding the chain of the manacles over his head was released. Itachi considered the fact that he was still cuffed, but now had about a half-metre of loose chain between his wrists.
Well, as much as he always questioned good luck when it occurred to him (just in case it was a trap, Itachi hadn't gained his S-ranking by being complacent) sometimes Itachi had to remind himself to never underestimate the stupidity of his enemy.
It was the work of seconds to wrap the chain around the Sound-nin's neck and to then use it to silently choke him to unconsciousness. Itachi considered holding on a bit longer, to kill him, and then did so. It didn't pay to leave live enemies behind oneself. They tended to try back-stabbing, and dodging preventable attempts on his life was an irritation that Itachi tended to avoid when he could.
Civilians had a saying, that a stitch in time saved nine.
Ninja had a saying that one didn't have to practice vigilance against dead enemies.
Itachi liked the second saying better. It spoke to him.
Dropping the corpse, Itachi proceeded to loot it for weapons and useful equipment. Itachi was irritated to note that not only were the corpse's boots far too big for him (Itachi was wearing a baggy grey jumpsuit and no shoes) but the corpse was not carrying the key to his cuffs. Still, he was able to leave the cell now, and he could probably get out faster if he was able to use jutsu, so he decided to just put up with the chain for now, and leave his thumbs intact.
Besides, as he had just displayed, the chain made a useful weapon, in a pinch.
Not that there were many things that Itachi couldn't use as a weapon, come to think of it, because he was nothing if not creative, (civilians might play "I spy" when bored, but most ninja of Itachi's acquaintance barring Tobi had always preferred, "Death by teacup", in which the winner was the one who could come up with the best way of killing someone with a random object,) but Itachi decided that was beside the point.
Having acquired a brace of kunai, some brass knuckles and some chakra pills from his enemy's corpse, Itachi left the cell and moved for the exit. He assumed he was underground, going by the smell and ambient light levels, so he went looking for a set of stairs. He killed everyone he encountered along the way, generally before they had time to do more than blink in surprise at him.
Well a few gave him some minimal trouble, but Itachi was almost starting to feel offended.
Did none of them know who he was? Did they never leave this dungeon? Was that what rock they'd been living under?
And what the hell was he doing in a Sound stronghold? Itachi had thought that they had mostly disbanded after Sasuke killed Orochimaru's last host-body.
Ah well. It wouldn't be the first time his intel had been wrong.
Finally, Itachi felt fresh air on his face.
Unfortunately that fresh air was from the door to the outside opening, and seven shinobi walking in.
Fortunately, two of them looked Itachi right in the eyes.
He cast a quick genjutsu on the fly to make them think that they were surrounded by enemies, tossed his remaining kunai into the throats of two others, and ducked behind a handy pillar.
A bare minute later, and the two shinobi he had turned were both dead, but only one of the original seven was left standing, and he was bleeding from a rather deep belly-wound.
Itachi picked up a handy rock from the ground and nailed the shinobi in the temple with it. He collapsed.
Itachi, knowing he had very little time, looted the cleanest-looking jacket that looked like it would fit him, retrieved his stolen kunai and added a few to a pouch he had lifted from one of the shinobi, and picked up a tanto that was of at least serviceable quality.
One of the shinobi looked to be about his size in sandals. Itachi was pleased to find that the sandals were indeed about the right size, and the shinobi did not have athlete's foot.
One of the other dead shinobi even had a pack with some travel rations still left in it. Itachi took this too.
Itachi stepped outside, not bothering to pause to breathe in the fresh air, although he did enjoy being outside the dingy compound.
His hands were still bound with the chain, but otherwise, things were looking up.