"Have you enjoyed your vacation in this time period?" asked Karasuki, the sea turtle-shaped Ōtsutsuki time-travelling device. "Are you ready to return home?"
The shinobi of the past having somehow defeated the Ōtsutsuki who had given them so much trouble, Boruto and Adult Sasuke had decided to return to the future; before they caused any more trouble than they already had.
"I have a question for you," said Sasuke quietly. "The past was nothing like I remembered it being— is this really our past?"
Karasuki blinked.
"Oh dear," it said with its electronic voice. "It appears that the timeline has been modified by a third party."
"What's going to happen to us, then?" asked Boruto worriedly. "And how come we still remember how things are supposed to be, like Sasuke-sensei's wife being—"
Sasuke shot his apprentice a dangerous look, so Boruto quickly shut up.
"Originally, had none of you travelled back to the past, nothing would have changed for your timeline— it would have simply remained a branch of possibility among a myriad others. However, by actually observing the changes made to the past for yourselves, you have made them a certainty— the what-if that was your future no longer exists, and the eventual outcome of this time period will eventually become your new future," explained Karasuki. "As for why you still remember how things used to be, it is because I come equipped with a paradox-inhibiting field. You are protected from any changes made to the timeline for the safety of the time stream."
Imagine going back in time to kill your own grandparents before the birth of your parents— you would no longer exist in the future you'd come from, but at the same time, there would no longer be anyone to kill your grandparents— which would result in your birth, which would then result in you bringing about your own non-existence once again in an infinite loop; and that's the grandfather paradox.
"T-then, what's going to happen to us?" Boruto stammered. "What will happen to everyone back home!?"
"There is only one way to find out," Karasuki answered calmly. "Shall we return to the future?"
After everything that had happened, Tsunade and Jiraiya had refused to have their memories erased, and neither had they accepted to hand over Urashiki's body to Sasuke.
Since there was nothing more that could be done to preserve the future, it was time to go.
"Do it," said Sasuke.
----------------------------------------------------
"Sasuke-san, it looks like we've made it back to our time!" shouted Boruto excitedly, as the colourful time bubble receded back into Karasuki's carapace. "The seven heads are still on Hokage rock!"
Tsunade, Kakashi, Naruto… those were definitely the stone faces they knew. The future didn't look especially apocalyptic, so it seemed like their trip to the past hadn't changed too many things, after all…
"I'll head to the Hokage residence to give Naruto my report," said Sasuke. "You head home and see if your family is still there. If they aren't, meet me back here. I'll hold on to Karasuki…"
Without waiting for an answer, Sasuke jumped off the roof of the building they had reappeared on and rushed to the Hokage residence, his heart pounding with apprehension as he pushed open the door to the Hokage's office.
As he walked up to the Hokage's desk, Sasuke noted that Naruto didn't appear to have changed, much to his relief— he was the same old Naruto he had always known…
"Any news about Urashiki's whereabouts?" Naruto asked him grimly. "He completely fooled us with that decoy, so he could be literally anywhere…"
"Urashiki is dead," said Sasuke bluntly. "That's the last of the Ōtsutsuki we know of."
He then began explaining to Naruto everything that had happened to him and Boruto. Naruto listened to his tale patiently, only interrupting to ask questions, but Sasuke could tell that something was bothering his friend.
"Well, that's a relief," said Naruto, once Sasuke had finished recounting his adventure. "But… what the!?"
Naruto had finally noticed the thing that had been bothering him since the moment his best friend had first walked into the room.
"Sasuke, where'd your left arm go!? Why the hell wouldn't you lead with that— oh, forget it, I'll call Tsunade— I hope you kept it on ice, or something…"
For an instant, Sasuke's eyes widened in surprise, but he quickly mastered his emotions. It appeared that in this timeline, neither of them was supposed to have lost any limbs after their second fight in the Valley of the End… if those fights had even occurred to begin with.
"No need," he said brusquely. "It was completely destroyed."
"Ugh… it's going to be so expensive to clone you a new one, ya know," Naruto groaned, holding his head between his hands. "Still, no need to worry— I'm sure the village's budget can take a little arm or two… I think."
Sasuke smiled weakly.
"Well, at least you haven't lost your most important limb," said Naruto jokingly, winking at him. "You've done an amazing job, so I won't keep you any longer… go home already, you lucky dog."
In men's terms, you're a lucky man basically means, I'd do your wife if I could— and Sasuke wasn't sure if he really appreciated the dirty expression on Naruto's face when he had said those words…
And so, Sasuke hurried back to his wife's apartment— only to experience a mini heart attack upon finding strangers in his home instead of his family. Remembering how his wife had accidentally destroyed their first house with her chakra enhanced strength, he then headed there… only to find a Lightning Burger franchise instead.
As he approached the building to ask for directions, Sasuke spotted his daughter Sarada through the window, so he hurried inside.
"Like, I'm so jelly," said Chōchō, the girl sitting across from Sarada. "How can you eat so much and stay so thin all the time?"
Akimichi Chōchō was Chōji of the Leaf's and Karui of the Cloud's plump daughter, and she was also Sarada's best friend. But strangely enough, her appearance didn't quite match Sasuke's memories of her; she was no longer dark-skinned, and her face was completely different…
"The calories all go to my chest," Sarada humble bragged, patting her chest. "I inherited my mum's genes, I guess."
Sasuke couldn't help goggling at his daughter, who had used to be as flat as a board. His expert eye told him that her chest had to be on the larger side of an E-cup— they were even bigger than Chōchō's, who was cheating by virtue of being obese.
"Oh, there's my dad," Sarada groaned, spotting Sasuke standing awkwardly in the entrance of the burger place. "See ya later, Chōchō."
"Cya," Chōchō mumbled through a mouthful of burger.
Sarada dumped her burger wrappers into a rubbish bin and walked straight past him to the exit without a word, so Sasuke decided to follow her— she was bound to know the way home.
"Are you coming home tonight, Papa?" Sarada asked him slightly coldly, as they walked side by side. "Or are you spending the night out again?"
"Yeah," Sasuke answered lamely. "I've just completed a big mission, so I'll be resting at home, for the time being…"
Sarada snorted derisively, and to Sasuke's surprise, she began leading him to the outskirts of the village, where the Uchiha District had used to be before it got obliterated by Pain along with the rest of the village. Strangely enough, it looked exactly like he remembered it being— minus the blood splatters and the corpses lying everywhere, of course.
Eventually, Sarada stopped in front of a large mansion, which to Sasuke's stupefaction, he recognised as his old house. Sarada knocked at the door, and after a few seconds, the door opened, revealing a raven-haired kunoichi's figure in the Entrance Hall.
"We're home, Hikari-mama!" Sarada told the woman. "Is mama home yet?"
"Welcome home, Sarada!" said the woman named Hikari, patting Sarada's head affectionately, before looking at Sasuke. "And welcome home... dear."