Sasuke is a courier with no memory. Countless express delivery are delivered every day, shuttled among the comings and goings of people.
By chance, he delivered a courier to Itachi Uchiha's doorstep. Itachi recognized Sasuke immediately, but Sasuke failed to recognize Itachi.
So under Suigetsu's behavior of 'buying teammates and pulling red strings', Sasuke finally successfully moved into Uchiha Itachi's house, and the following story began.
"My stupid brother."
[This is my first time writing a copy - -, don't mind if it sucks]