Years past, both Sasuke and [name] are 16, [name] was living the childhood she couldn't continue along with Naruto and Sakura.

"[name], I'm going a trip with Pervy Sage." Naruto said excited.
"Oh? Is that so? I'm so happy for you, Naruto." the girl said.
"I'll also look for my friend, Sasuke. I don't remember if I told you about him." the blonde-haired boy said.
"Sasuke?" you make Naruto a sign to come closer "Don't tell anyone. If you meet Sasuke tell him i said hi." you whisper in his ear.
"You know Sa-" Naruto started screaming and you covered his mouth.
"Naruto-kun, is top secret. Don't tell anyone. I'll get in big trouble for it." you said and Naruto simply nodded. "Have a safe trip Naruto." you said as Naruto had to leave.
"You know you shouldn't do that, do you?" Kakashi asked from behind you.
"I know, sensei, but it's been a long time. Plus the third hokage isn't anymore and Tsunade-san doesn't really care about it." you said.
"Well don't say i didn't told you." he said as patted her head.

Meanwhile, on the other hand, Sasuke was ready to fight his brother. He waited long enough, is revenge for his clan and for [name].

"You chose a strange place, Itachi." Sasuke said as he walked closer to his brother.

"That sharingan, how much can you actually see with it?" Itachi asked.
"I see your death." Sasuke said.
"My death? Only my death, my foolish litlle brother?"

▪︎▪︎▪︎

"Tell me, what is the sacrifice of a [last name]?" Sasuke asked being trapped in Itachi genjutsu.
"You heard about it?" Itachi said. "Is not much to said about it. If you know that a sacrifice exists you probably know the rest."
"Then, where is [name], what did you did with her?" Sasuke screamed making Itachi laugh.
"I didn't call you foolish for no reason. If you were more careful at the details, you knew until now." Itachi said.
"She was nowhere to be found." Sasuke said annoyed making Itachi laugh again.
"She was right under you nose. Her father talked with the hokage, in case both of her parents will die, to make [name] disappear with them so she won't have to make any sacrifice for you. She was send to Kakashi, your sensei, and stay with him until both of us will be death or when it will be shown that you know nothing about a sacrifice." Itachi explained to him.
"You mean she's alive?" Sasuke asked.
"She probably is."