Encounter! The Boy with a Star's Name

is episode 178 of the original Naruto anime.

Synopsis
Tenten, Neji, and Rock Lee were assigned to a mission to protect the star belonging to Hoshigakure. When Naruto heard of the star's special chakra enhancing power he decided that he too must go along because of his assumption that Orochimaru may be involved. Naruto manages to convince Tsunade to allow him to join Team Guy's mission by bribing her with an expensive treat. Naruto and Team Guy encounter Sumaru of Hoshigakure, who guides them past the poison gases that surround the village after demonstrating techniques with strange purple chakra. The Konoha genin meet with the substitute Hoshikage, Akahoshi, who explains Hidden Star's desire to become one of the Five main Hidden Villages. Sumaru expresses his desire to become the first true Hoshikage of Hoshigakure, which intrigues Naruto who rushes off after Sumaru in the direction of the place where the village's star is held. Naruto and Sumaru see someone fleeing from the building containing the star and Naruto runs off in pursuit. Sumaru discovers that the star has been stolen and chases after the thief. The thief manages to escape from Naruto, and it is revealed that the user was using techniques exclusive to those who had star training, meaning they were once a member of the Hoshigakure.