Chapter 628 is titled "Major Cleanup".
In the streets of a town, the fumi-e of Queen Otohime continues. Hody Jones declares himself the new king, demands that anyone who wishes to befriend humans to be banished and broadcasts Neptune being held captive. He announces that he will execute Neptune within three hours in Gyoncorde Plaza. The box containing the petition signatures is with him, and anyone whose name is on it will be executed one by one. At the end of the speech, he leaves a message for the Straw Hats saying that he's going to execute Zoro, Usopp, and Brook by filling the room they are in with water. At the end of the communication, Shirahoshi and Luffy decide to go rescue the prisoners, but Jinbe tries to stop them. While he is able to stop the mermaid princess, Luffy wants to defeat Hody Jones himself and rescue his friends. But Jinbe is so firm in keeping Luffy from fighting Hody which may result in more tension between races, that he and Luffy prepare to fight each other.
A citizen is being forced to step on the fumi-e of Otohime. Daruma remarks how boring it is, since everyone is stepping on it, albeit reluctantly. Hody Jones' broadcast then starts. He declares that Fish-Man Island will collapse and be reborn under the new king, himself. These announcements make people wonder what happened to Neptune and the Straw Hats. Jones then declares that anyone who is seeking peace or friendship with humans should leave the island. He tells the people that residents of the Fish-Man District are migrating to the main area of the island, all of whom hate humans. This terrifies the people watching the broadcast. Jones adds that humans will continually betray them, no matter how nice they seem to act. The three princes are watching the broadcast, all furious. He tells them that the path Neptune is leading them on only leads to death. He then shows the tied up Neptune, much to the shock and anger of his children as well as everyone watching. Nami realizes they were the ones who caused Neptune to be captured, citing Zoro in specific. Jinbe is shocked by this news and asked Nami what they are trying to do. Camie tries to tell him that it was a misunderstanding started by the palace guards. Jones then says it is time to bid farewell to the current Ryugu Kingdom, and that in three hours, he will take Neptune's head in Gyoncorde Plaza.
Hody holds a piece of paper and a box next to him filled with thousands of papers. They are the letter from the Celestial Dragons and the petitions that Otohime collected. He calls the petitions as a list of traitors. The petitions will serve as a more comprehensive black list of who is with him and who is against him. Jones then addresses the Straw Hat Pirates. He shows them Usopp, Brook, and Zoro locked in a cage. He tells them that after the king is executed, the room they are in will have filled with water, drowning them. He then holds up Luffy's wanted poster, saying he will take the captain's head as well and show it to the people on the surface. He then declares that the cleansing of Ryugu Kingdom will begin and that in three hours Fish-Man Island will be reborn as a nation of pride. Fukaboshi declares he will not let that happen.
In the royal palace Usopp, Brook, and Zoro are locked away. Zoro tells Usopp to open the lock, and Usopp commands it to open. Brook was thinking about when someone was surprised to see him move, thinking he was a fake skeleton. Usopp and Zoro angrily tell him that if he had played dead he could have escaped. Brook then makes a dead joke. Zoro then says it was a good thing Nami and the others got away. Usopp then does an impression of Robin, commenting that Nami might have been eaten by a deep sea fish, making Brook laugh.
In the Sea Forest Robin is examining the poneglyph in the forest, saying it is different from the ones she has read up until now. It is written like an apology letter, mentioning someone called Joy Boy. Robin wonders who that is. Back at the ship, Luffy is excited over his bounty going up. Nami slaps him and Sanji says it is obvious the New Fish-Man Pirates want to pick a fight. Jinbe remarks how high Luffy's bounty is, and then tells Luffy to wait before going to fight Hody. Shirahoshi then tries to take off for the palace on Megalo, but Jinbe stops her as well. Jinbe reveals that Hody Jones is terrified of Shirahoshi's ability to summon Sea Kings. Shirahoshi is the one true threat to his plan. Hatchan adds that he is using the king as a shield against her. The reason Jones even teamed up with Vander Decken IX is because he was already after the princess' life. Shirahoshi explains that she knows about her power, but has never actually spoken with Sea Kings, she is not even sure if she has the ability. Jinbe says that Jones cannot find out, and his fear alone should be enough to keep him away.
Luffy then tries to take off on Megalo, high-fiving Sanji and telling him to take care of "weakling". Jinbe stops him, saying Luffy must not fight Hody. Chopper and Franky asks if it is because they are humans. Jinbe tells Luffy to leave it to him. Luffy replies that his crew is being held hostage, and as the captain he must save them. Jinbe tells Luffy that if he does not stop he will have no other choice but to fight him.
- The cover page gives a glimpse of the Straw Hats' new abilities:
- Nami appears to have upgraded her Clima-Tact, as it appears to be lighter and it does not have the dials visibly attached.
- Usopp is shown with several different pellets of various colors.
- Chopper is shown in his new Horn Point.
- Franky has a cannon mounted on his shoulder.
- Brook's skull is floating and is separated from his body.
- Robin is able to create a full copy of herself.
- Zoro, Usopp, and Brook are locked in a room with rising water.
- Hody announces his plan to execute Neptune in three hours, followed by the execution of the citizens who gave their signatures on Otohime's petitions
- Fukaboshi apparently defeated Dosun as he stands uninjured along with his brothers.
- Robin discovers a new poneglyph but it seems to be different. The message is more like an apology letter and mentions about someone named Joy Boy.
- The meaning of the other half of Jinbe's message is revealed, as Luffy (a human) fighting Hody would only cause a rift in the migration.
- Luffy learns about his new bounty, which is odd since in chapter 599, Demaro Black yells the bounty right to his face, although it is likely that Luffy did not realize who he was impersonating.
- Jinbe and Luffy have a disagreement and they prepare to fight each other.