The End

is episode 138 of the Naruto: Shippuden anime.

Synopsis
While Sasuke summons Kirin, and when he thinks that he finally defeats Itachi, Itachi starts to get up and shows his ultimate weapon, the Susano'o; Sasuke tries to draw out more chakra, using up the chakra that was suppressing Orochimaru, allowing the latter to emerge from Sasuke's Cursed Seal. However, Itachi permanently seals away Orochimaru using the Totsuka Sword. With no more jutsu at his disposal, Sasuke is left at Itachi's mercy as he goes right to him with the intent of taking the eyes of his little brother. But at the last second, Itachi tells Sasuke "I'm sorry Sasuke, there won't be a next time" then suddenly dies. It's actually what he tells Sasuke when he was young whenever Sasuke wanted to train with Itachi, "I'm sorry Sasuke, maybe next time" but because he dies, he says won't be instead of maybe. Usually he flicks Sasuke's head but here he just holds his forehead.