Kurenai's Decision: Team 8 Left Behind

is episode 203 of the original Naruto anime.

Synopsis
Naruto encounters a girl named Yakumo, who, by drawing a picture of Konoha, causes lightning to strike Tsunade's mansion. Shortly thereafter, Kurenai Yuhi resigns as leader of Team 8, and Naruto is determined to find out why. Later that night, Naruto - disguised as Kurenai - goes into Yakumo's mansion and discovers a room full of Yakumo's paintings. He escapes after one of the paintings nearly kills him, and is confronted by security, who tranquilize him.

As it turns out, Kurenai was assigned by Hiruzen Sarutobi to act as Yakumo's "sensei" in Genjutsu, since Kurenai herself was quite adept at it. However, Kurenai and the Third Hokage discovered that Yakumo's true talent hadn't fully awakened, and could very well destroy the Hidden Leaf Village later on. So, Yakumo's ability was sealed by Kurenai. Yakumo thought that Kurenai hated her, and that the Third Hokage had ordered Yakumo's parents to be killed. Those thoughts led to Yakumo's breakdown, when she nearly kills Kurenai in a Genjutsu, which is broken by Team 8, with the help of Naruto and Sakura.