[A/N: Sorry it's taking so long to post this! I started overthinking stuff and got discouraged, but I'll try to work on it more now.]
Prologue:
Itachi carefully shifted Sasuke's sleeping form in his arms as he bounded through the forest. With the heavy genjutsu he was under, the child was almost a dead weight, and feeling heavier and heavier as Itachi continued travelling for hours.
Itachi could not regret what he had done that night, although he could and did grieve over it. While he had respected his family, he could not allow anything to destroy Konoha's delicate and carefully cultivated peace. But still, he had hated the thought of leaving Sasuke to grow up with nothing, or worse than nothing.
It had taken him weeks of research, but he had eventually found a satisfactory solution. That is, if it worked the way he hoped it would.
The forest which covered most of Fire Country and River Country was fading away now, and Itachi knew he was nearing the border of Wind Country. Suna Village would not be far off. Now, if only he could bring himself to go through with his plan…
After vaulting up to the top of the village wall and down into a deserted alleyway, Itachi set Sasuke down and formed the seals to henge into the appearance of a nondescript young woman in a Suna chuunin uniform. He had already removed the Uchiha symbol from the back of Sasuke's shirt, taking care not to leave any evidence behind.
Picking Sasuke up again, he headed toward his final destination—he had chosen this place on another mission, several months before. There really weren't very many options, in any case. Suna didn't have nearly so many orphanages as Konoha, since they had never had a natural disaster on the level of a rampaging Kyuubi.
A harried-looking young woman came to the door as Itachi knocked. "Yes, what is it?" she asked, absently patting the brown hair of the little girl clinging to her apron.
"Yoshiko-san, who're they?" the girl whispered loudly, her eyes big as she stared at Sasuke.
"I don't know yet, Akiko-chan," the woman replied. "You go back to bed now."
The little girl scampered away and Itachi knelt to set Sasuke down, slowly releasing the genjutsu he was held under. "I found this child wandering the streets a little while ago," he said. "As far as I can tell from what he would say, his parents are dead."
"Oh…" the woman sighed, kneeling down as Sasuke opened his eyes. Itachi prayed silently that his research really had paid off—he hadn't had a chance to test it before. "What's your name, dear?"
The boy blinked slowly, as if not sure how to answer the question. "Yuki," he said finally. "My name is Yuki."
Itachi sighed, almost saddened at his success, before turning away and vanishing from his brother's life.
[A/N: Yeah, I love amnesia fics way too much...]