The Search for the Rare Bikōchū Beetle

is episode 148 of the original Naruto anime.

Synopsis
Naruto was frustrated by Mizuki's inability to lead him to either Sasuke or Orochimaru, and began pestering Tsunade to allow him to go look for him. Hinata sympathized with Naruto, and suggested trying to find a way to help him. Shino commented that a Bikochu, a very rare insect, would be able to track down Sasuke if it smelled his scent. As Kurenai Yuhi was hospitalized for injuries that she had suffered during the prison break, Shino was tasked with leading Team 8 to find the Bikochu, and Naruto joined with them as the fourth member. It was also revealed that Hinata was practicing a new defensive technique, and had nearly mastered it, and was seen training naked at a waterfall by Naruto at night, though he did not recognize her. The next morning Naruto told Kiba about the "ultra-pretty" girl he saw, embarrassing Hinata greatly.