Roar, Chidori! Brother vs. Brother!

When Naruto opens a door and comes eye to eye with Itachi, he is struck by how closely the stranger resembles Sasuke, right down to the Sharingan. Across the village Sasuke sprints through the streets in a frantic hunt for his brother, his mind drifting back to boyhood. As a small child he idolized Itachi, once begging him for shuriken practice only to be waved off, then asking their father why his brother never had time for him. Fugaku called Itachi guarded and hard to know, and Sasuke's mother Mikoto handed him his lunch before he left for the Academy.

On the way to school a relative reminded Sasuke that Itachi had unlocked his Sharingan and made genin by that same age, deflating him, though his uncle Teyaki insisted his time would come because Uchiha blood ran in him too. Returning home after dark, Sasuke found the streets strewn with slain relatives and blood-marked walls, then discovered his parents dead. Confronting Itachi, he demanded a reason, and Itachi coldly claimed he had wiped out the clan to gauge his own strength, dismissing Sasuke as not worth killing and urging him to live consumed by hatred.

Back in the present, as Kisame and Itachi debate how to transport Naruto, Sasuke reaches them. Kisame marvels at the resemblance and the shared Sharingan, and Itachi identifies Sasuke as his brother, amusing Kisame who thought the whole clan dead. Sasuke declares his life has been built entirely on the wish to kill Itachi and rushes in with Chidori, which Itachi halts effortlessly. Naruto draws on the Nine-Tails' chakra to summon a toad, but Kisame's Samehada devours the chakra; before he can strike Naruto, a toad and then Jiraiya arrive to block him.

Adapting chapters 145 and 146 within the Search for Tsunade arc, the episode carries the opening GO!!! and the ending Many Times Before. It aired in Japan on May 19, 2004, and in English on April 21, 2007, weaving the massacre flashback into the brothers' confrontation.