Chapter 596 is titled "SPECTRUM".
Nami fools the citizens of Weatheria once again and decides to stay behind to study the weather patterns of the New World such as a lightning rain on one of the islands. Haredas points out that weather in the New World is so dangerous that one needs to have good navigational skills to survive the weather of the New World. Nami talks about how reckless Luffy is and how he has no sense of direction. So Nami insists she must learn how to navigate through the most dangerous weather in the New World so she can help him become the Pirate King. Nami also begs Haredas to also teach her about the Weather Balls they create, however, Haredas is a little hesitant as he feels the invention should not be used as a weapon. Though this does not stop her from smirking about the idea.
Brook is now behind bars in a cage and he is on display as a freak show. The Longarm people of Kenzan Island get a little frustrated as Brook is motionless reading the newspaper and thinking about the moment when Luffy recruited him to the Straw Hat Pirates. He tries thinking of how he can help Luffy. Brook then comes to the decision that he is going to be more useful for Luffy and then falls over at a 40 degree angle and suddenly gets up. He is seen wielding a guitar in front of the Longarm people and begins playing a song called "Bone to be Wild".
Robin departs on a ship with the Revolutionaries. And for once, the Revolutionaries appear to be a group of people who actually hold no hatred for Robin, as she has been used to being hated by people since she was said to be a demon child. The Revolutionaries set sail for Baltigo because their leader Monkey D. Dragon wishes to meet Robin. The Revolutionaries ask Robin to get inside the ship where it is warm however Robin chooses to stay due to her nature of not trusting anyone. The Revolutionaries then give her lots of blankets and take all the warm food they made for her outside so she could be comfortable. In the end, Robin decides she was going to get stronger not for herself, but for Luffy as well, she even seemed surprised that she was thinking that way.
The Marines are now looking for Franky for causing the biggest disaster on Karakuri Island. The people on the island confuse Franky for a cyborg gorilla and the Marines begin taking that into consideration, believing that it might have been a cyborg gorilla that caused the explosion of Dr. Vegapunk's lab. Franky is in the part of Vegapunk's lab uncovered by the explosion. He begins studying everything Dr. Vegapunk had made blueprints for, especially the weapons. So, Franky then decides to live in the lab and learn about all the technology that Dr. Vegapunk designed so he could help improve the Thousand Sunny's battle capabilities as well as his own. He would use the locals' houses to store his cola and only come down when he was running low. The two locals he was staying with, however, are frightened by his current look (which is the result of being in the explosion of Dr. Vegapunk's first lab). So, Franky decides to wear a tiger rug over his face so he will not look weird. The rug gets too close to the flame and catches fire. Franky runs out of the lab completely on fire and screaming. The Marines pursuing him see him run out of the lab, but to them he looks like a fiery tiger demon and frightens them into running away crying. What the Marines saw would come to be known as "The Legend of the Sacred Burning Beast of Baldimore".
Usopp now realizes that he must get stronger and indeed he must lose weight. He also realizes that Luffy does not always win the battles like he always thought. So, he decides to become Heracles' pupil so he can get stronger. Heracles, who is rather excited about the idea, begins teaching Usopp about the secret to surviving on the Boin Archipelago, which happens to be a plant called Pop Green that possess instantaneous growth and hold various other uses. So, Usopp decides that in order for Luffy to become the Pirate King, he was going to become the true Sniper King.
- On the cover page, a grown-up Sabo is shown.
- It is confirmed that the crossed out S in Ace's tattoo was really a tribute to Sabo.
- Franky again terrorizes the people of Karakuri Island with a new legend, this being "The Legend of the Sacred Burning Beast of Barujimoa".
- Brook creates a new song called "Bone to be Wild" which is a parody of the song "Born to be Wild" by the band Steppenwolf and a pun on Brook's appearance as a skeleton.
- It is clear that almost all of the Straw Hats (except for Zoro, who was not shown) understand Luffy's message to get stronger.
- first introduction
- first apparition