Chapter 642 is titled "Complete Loss of Face".
The inhabitants of Fishman Island are told to evacuate the island because Noah might crash into it. Neptune is told that the evacuation began and has to evacuate as well, but he stays. In Gyoncorde Plaza, the Straw Hats are fighting the New Fishman Pirates and Robin is asked by Jinbe to free the human slaves. Wadatsumi reveals his puffer fish ability and Sanji gets on his head and provokes him to inflate himself more and destroy more of the plaza and everyone in it. Franky gets fooled by Ikaros Much's ink double, but attacks him with a fireball. Chopper gets distracted by it for a short time and almost gets hit by Dosun's attack, managing to repel it with his improved Heavy Point. Hyouzou jumps at Zoro as he is talking to Chopper, but ends up getting his swords cut by Zoro.
In the Sea Forest, Den notes that something is going on on the island, as all the animals have left. Hatchan says there is no way to break Hody Jones, calling him the true terror of their boss Fisher Tiger. Around the island, an emergency broadcast warning is going out, with the Minister of the Left ordering all citizens to evacuate the island immediately. He confirms that the large object that will hit the island is Noah. People are also getting word from the plaza that Shirahoshi was the one who led Noah away and that Vander Decken IX is behind Noah's arrival.
The Minister of the Left and some soldiers approach where Neptune is resting. The minister apologizes, saying they let him down. Neptune mentions that if Noah hits the island, it would be just as it was written. The Minister of the Left tells Neptune about the evacuation and encourages the king to leave as well. Neptune says the orders are fine but he will stay and wait for the princes.
At Gyoncorde Plaza, the Minister of the Right and more troops are surveying the battle from the perimeter of the plaza, confused as to why there are so many pirates. Some bystanders get him up to speed about what happened before he arrived. The Minister of the Right orders the Neptune Army to back up the Straw Hat Pirates in the plaza, saying the country's honor would be shattered if they were backed up solely by a gang of pirates. He then orders the people watching the battle to evacuate. The people refuse, saying that since the Straw Hats are fighting for them, it would be shameful to run and leave them, so they might as well throw their lot in with the pirates and stay. The Minister of the Right tells them to do what they feel is right as he dives into the plaza to join the battle. The arrival of the army does not intimidate the New Fishman Pirates at all. Hammond then arrives, riding something he calls his slave tank, essentially a large rickshaw with cannons, pulled by human slaves. One of the slaves falls over exhausted and Hammond just says to leave him.
Wadatsumi breathes in and expands his stomach, calling himself "Meganyudo", becoming even larger than before. Sanji asks if that had a point, saying the kraken was still bigger than him. This angers Wadatsumi and he expands even more, crushing everything within range. Sanji is still unimpressed, and Wadatsumi is about to expand again. Jinbe asks Nico Robin to free the slaves, saying he cannot sit back and watch Hody copy the World Nobles. Ikaros Much is using a spitting attack on Franky, calling it Ikaros Wings. Franky punches him but it just goes through, as Ikaros reappears behind Franky saying that was his squid ink clone. Franky uses Franky Fireball and Ikaros narrowly dodges. Chopper and Dosun match each other with Heavy Gong and T-Shot, respectively, causing Zoro and Chopper joke about how he looks like a monster. Just then, Hyouzou comes at Zoro, saying he will chop up anyone who laughs. Zoro intercepts the attack and cuts off several of his swords' blades perfectly at the hilts, asking for the strongest swordsman on Fishman Island. He then asks Hyouzou how he is going to kill him, when the octopus merman could not even kill Zoro's boredom.
- Den, Keimi, and Hatchan remain in the Sea Forest.
- The inhabitants of Fishman Island start evacuating the island.
- The Neptune Army recovers and arrives to back up the Straw Hats.
- Wadatsumi demonstrates the ability to blow himself up like a balloon.
- Hammond is seen using human slaves to pull a weapon he was operating called the "Slave Tank" in a disturbing display remnisicent of the World Nobles, and truly a sad sign of the true mental instability of the fishmen gang.
- Chopper shows his new Heavy Point transformation.
- Ikaros Much and Dosun both reveal named attacks.
- Zoro manages to cut through Hyouzou's swords.
- This is the first chapter in which Oda painted the color pages with watercolors and red ink instead of Copic markers.