The Longest Moment

is episode 135 of the Naruto: Shippuden anime.

Synopsis
As Sasuke approaches the Abandoned Uchiha Stronghold, Itachi recalls his past with his little brother and the assassination that he carried out after joining the ANBU and being under close watch for his suspicious activities. When Sasuke arrives, he declares that his eyes have shown him Itachi's death and the fated battle begins between the two brothers begins. Itachi's illusions deceive Sasuke as he explains that he conspired with Madara Uchiha, Konoha's founder and the first to awaken the Mangekyo Sharingan, when he killed their clan.