Naruto S02 E98 Tsunade's Warning: Ninja No More!

Naruto, Tsunade, and Shizune finally return to Konoha so Tsunade can take over and become Hokage. Konohamaru finds out that Tsunade is the Fifth but refuses to believe it. Naruto then takes Tsunade to the hospital so she can heal Sasuke, Kakashi, and Lee. She heals Sasuke and Kakashi just fine...However, her diagnosis of Rock Lee has heartbreaking consequences for him and his future.