Naruto: Season 3, Episode 131

3 - 131: The Secrets of the Mangekyō Sharingan

While Naruto is busy underwater, Sasuke remembers the fateful day in which his clan was killed. He remembers why Itachi spared his life, and why Itachi did what what he did. Now, in order to gain the same power as his brother, he must kill his closest friend...Naruto!