"I Will Be Stronger! Zoro's Vow to the Captain" is the 515th episode of the One Piece anime.
While being put on display in a cage, Brook feels appreciative towards all that Luffy had done for him and decides that he will move on and continue to aid Luffy. He takes out a guitar and plays "Bone to Be Wild", his new single. On the other hand, Robin has decided to go to Baltigo and meet Dragon. She has a flashback of all the times that she had to face hardships and could have been helped. Out at the Boin Archipelago Usopp decides to train for Luffy's sake. At Kuraigana Island, Zoro goes onto his knees and asks Mihawk to train him, in which Mihawk agrees. Zoro then explains to Perona the hidden message Luffy left for his crewmates.
The episode starts off with an island called Kenzan Island, home of the Tehna Gehna Kingdom in the Grand Line. A group of people are gathered to see some kind of freak show which turns out to be just Brook. Brook is holding a newspaper while the crowd is booing because he will not move. He will not move because he is remembering what Luffy had done for him and what he can do for Luffy. He has a flashback of when he first met Luffy and remembers how Luffy wasn't scared of him and how Luffy wanted Brook to join the crew. Brook tells the crowd how happy he is, because for fifty years he had been alone in the dark waters and then he has a flashback of Gecko Moria stealing his shadow and Luffy defeating him. Brook finally moves and stands up and talks about how he will become stronger for Luffy and then he starts playing a guitar, to which the crowd responds saying that it makes their heart skip a beat. Brook then declares that it is his new single, "Bone to be Wild".
The scene changes to where Robin is, under the giant bridge in East Blue and the revolutionaries are asking her why she suddenly changed her mind and decided to come with them to Baltigo. Robin has a flashback of Ohara being destroyed while remembering Saul's final words and what she had to go through, then the flashback switches to Luffy trying to save her in Enies Lobby and then Sogeking burning the World Government flag. The scene then turns back to the revolutionaries trying to make Robin go inside since it's cold but she refuses saying she is a pirate and they are revolutionaries and she could not trust them so easily.
The location switches to Usopp in the Boin Islands. Usopp is running with Heracles saying that he needs to lose weight then get much stronger. Then Usopp has a flashback of when he became a part of Luffy's crew and when he was at Enies Lobby cheering Luffy to stand up so they could leave together and continue their adventure. The scene changes back to him asking himself if Luffy could become the Pirate King without his help, but he soon realizes what he is saying and he tells himself that he needs to get much stronger. Heracles is touched by his words and he starts to teach Usopp about Pop Greens. Then in his mind comes the fact that if Luffy is going to become Pirate King, then he needs to improve and become the King of Snipers.
The location switches to Kuraigana Island where Zoro is begging Mihawk to train him to become a great swordsman. Mihawk is disgusted by what Zoro is doing and says if he cannot even beat the humandrills outside then he has no reason to train him to which Zoro replied by saying that he defeated all of them. Mihawk was surprised by this and agreed to train him but only after his injuries were healed. Zoro and Perona go back to their room and she asks why he wants to train all of a sudden. Zoro then explains Luffy's tattoo to Perona.
Characters in Order of Appearance
- The manga shows that all the humandrills have been defeated, but in the anime, there are some remaining, and the ruler of the humandrills is shown. It wields a sword similar to Mihawk's, but it has a white blade.
- The beginning of Zoro's training is shown with him fighting the head humandrill.