"Sensei and Student: The Bond of the Shinobi" (熱血師弟の絆～男が忍道を貫くとき～, Nekketsu Shitei no Kizuna ~Otoko ga Nindō wo Tsuranuku Toki~) is episode 100 of the original Naruto anime.
Guy and Lee discuss the operation, and Lee expresses his fears of dying as well as his fears of never being a ninja. The two reminisce about their time together, and Guy finally decides that if Lee dies during the operation, so will he, as he too can't live if Lee isn't a ninja. Guy's words inspire Lee, and he decides to take the operation. Tsunade, meanwhile, manages to increase the odds of Lee's survival to 58%, and is satisfied that Lee will most likely survive the operation. Tsunade is inaugurated as Hokage, and the role as the village's protector is passed on to her.