When Anko Mitarashi was assigned to escort a deliver shop and stop a sea monster mystery in the Sea Country, she was assigned Naruto, Shino, and Ino as all other active ninja were unavailable. Upon arriving at a village, Naruto met a young girl with several bandages name Isaribi. Naruto was shocked to learn that much like him Isaribi was shunned from the society and treated as a monster. Naruto tried to befriend her, but was too traumatized to embrace his kindness. Later when reaching the ship, Naruto and his team were attacked by Yoroi Akadō and Misumi Tsurugi from the Chūnin Exam. Naruto was knocked out and sunk to the ocean. Fortunately, he was saved by Isaribi. Later after catching up with his team, he discovers them spying on Isaribi. To their shock, the watch Isaribi transform into a humanoid sea creature. Unfortunately before they could figure things out, Yoroi appears and escapes with Isaribi. Naruto's team is unable to follow as Anko mysteriously faints.
After Anko recovers, reveals the truth about her past and this chain of islands. She tells her team that several years Orochimaru used this place as a base to conduct many of his horrific experiments. He was also responsible for the people mysteriously disappearing and used them as lab rats, as he did with Isaribi. These actions also started the legend of people being captured by spirits. Determined to make Orochimaru pay, Naruto insisted on destroying the hidden lab. While Anko was able to guide them to the lab thanks to prior knowledge she had as Orochimaru's former apprentice, they were ambushed by the enemy. Naruto was shocked to learn that Isaribi was working with the people who turned her into a freak. She explained that all she cared about was becoming normal again, which Amachi, the lead scientist of the lab, promised he would do. Naruto tried to convince her that this was wrong and that he understood her pain since he too has been discriminated against but Isaribi refused to listen. She then retreated with Amachi to attack the cargo ship. Naruto was stopped from following by Misumi, but was able to defeat him with Ino's help. After escaping with his team from the crumbling lab as a result of the all the fighting inside, Naruto and his team went after Amachi and Isaribi. Naruto then found himself up against Isaribi, but eventually managed to make her understand what she was doing was wrong.
Soon after, Amachi went up against Naruto and revealed to have put himself through the same surgery as Isarabi but fully perfected. Initially, Naruto was completely overwhelmed, but by tapping into some of the Nine-Tail's chakra, Naruto quickly defeated Amachi. He soon after collapsed from exhaustion, but was saved again by Isaribi who was compelled to save him after realizing Naruto really did understand her pain. Shortly after Naruto awoke, he and his team found themselves attacked by Amachi's spectral summoning. Naruto countered by summoning Gamabunta to help. Together, they were able to destroy it with an improvised fire jutsu. After discovering that Amachi had no idea how to restore Isarabi to her previous form, Naruto offered Isaribi to come back with him to Konoha in hopes that Tsunade's superior medical prowess would be able to help her.
Episodes
| # | Episode Title | Japanese Airdate | English Airdate |
|---|---|---|---|
| 169 | "Remembrance: The Lost Page" | 25 January 2006 | 24 May 2008 |
| 170 | "The Closed Door" | 1 February 2006 | 31 May 2008 |
| 171 | "Infiltration: The Set-Up!" | 8 February 2006 | 31 May 2008 |
| 172 | "Despair: A Fractured Heart" | 15 February 2006 | 7 June 2008 |
| 173 | "Battle at Sea: The Power Unleashed!" | 22 February 2006 | 7 June 2008 |