Naruto Episode 171: Sneaking: The Planned Trap
Episode 171 of 220 of Naruto, aired February 8, 2006, 25 minutes. Available with English subtitles and dub where released.
Episode summary
After Isaribi escapes, Naruto and his team decide to go to the forbidden island and confront Orochimaru and his subordinates. They soon discover that Orochimaru is not the man behind the curtain, but a man known as Amachi. Amachi is the one responsible for turning Isaribi into a monster, so why is she helping him?