Chapter 860 is titled "10:00 Opening of the Banquet".
Cover Page Request: "Crocodile holding out an umbrella for a puppy shivering in the rain" - Yuu Moritobi, Hyogo Prefecture.
In the eastern bay of Whole Cake Island, a bound Pekoms inquires what the Sun Pirates are planning. Aladine, recalling Jinbe's instructions to leave Big Mom's territory prior to the start of the Tea Party, informs Pekoms that they are deserting.
Minutes before the start of the tea party, the guests begin to arrive at the reception on the roof of Whole Cake Chateau. As the Vinsmoke Family makes its way through the castle, the final Underworld guests are escorted to the banquet by Perospero. At the gate in front of the venue, the guest Jigra refuses a body check from Capone Bege, but is immediately sniped by Sweet Commander Charlotte Katakuri, whose Kenbunshoku Haki informed him that Jigra was planning to murder Big Mom.
At 10:00 AM, Big Mom enters the tea party venue and the banquet commences.
At Whole Cake Island's eastern bay, Pekoms is asking Aladine where the Sun Pirates are going. Aladine informs him the crew is leaving the country, and Pekoms asks if Big Mom is aware of this while reminding about what happens to those who leave Big Mom's umbrella. Aladine lets Pekoms know how grateful Jinbe is. He recalls Jinbe's final address to the Sun Pirates, having learnt of Capone Bege's plan to assassinate Big Mom. While Jinbe is uncertain that the plan will work, he is glad (if shocked) to learn about Big Mom's own plan to assassinate Germa. Jinbe remarks that if Luffy finds out about this, he would surely do something rash to save Sanji. Not wanting this to happen, Jinbe declares his intention to help Luffy out and fully betray Big Mom. When recounted that when he tried to leave her crew honestly, she dragged out her penalty roulette, which is marked with numbers that, if chosen, indicates how many crew members would suffer along with Jinbe. Not wanting to subject them to such an absurd punishment, Jinbe orders the Sun Pirates to run before the Tea Party starts, because he knows security will be light as the ships are sent to escort guests. Aladine assures Jinbe that they would protect him in the same way he would protect them. Jinbe tries to brush it off, which angers Aladine, who can tell Jinbe plans to die. Jinbe tells Aladine of his intent to join the Straw Hat Pirates, and that, in doing so, it was only a matter of time before he put his life on the line to defend his new captain. Aladine understands Jinbe's intentions and tells him to do what he must. He then says that he and the crew will go back to Fish-Man Island, asking Jinbe if he was still worried about Ryugu, and Jinbe says yes. The flashback ends with Jinbe and Aladine reaffirming their friendship. Aladine then tells the crew to set sail, much to the abandoned Pekoms's dismay.
Inside Whole Cake Chateau, the Vinsmoke Family makes its way to the ceremony venue, which Judge explains is on the Chateau's roof. Behind him, Yonji asks Reiju where she was the previous night. Reiju brushes it off, lying that she requested a change of room to escape the ruckus of their drinking and celebrations. Niji patronizes his brother, telling him to keep out of other adults' business. Niji then confirms with one of Big Mom's subordinates that Sanji was preparing for the ceremony, which leads Reiju to ask herself what Sanji was planning on doing.
Outside, the homies are getting excited as the ceremony's start draws closer. A pig-drawn carriage hurries in and stops before a welcoming crowd, with some remarking how late they are. The Underworld guests then step out of the carriage and proceed to the entrance of the Chateau: the Black Market King, "God of Fortune" Du Feld, "Queen of the Entertainment District" Stussy, "Major Undertaker" Drug Peclo; the president of the World Economic Journal, "Big News" Morgans; Giberson the Concealer, a leader in the storage industry; and a shipping magnate, "Deep Current" Umit. Du Feld and Peclo trade barbs, each asking the other why they were invited, but are silenced by Stussy. Morgans comments about what big news the marriage is, while Giberson and Umit note how it was already common knowledge in the Underworld. Charlotte Perospero then welcomes the guests and prepares a candy escalator to take them to the roof, explaining that they are the last guests and that Big Mom hates latecomers. The guests marvel at the escalator's craftmanship, before boarding. Perospero then gives some lollipops to some nearby waiting children, telling them that they can eat the escalator in a few minutes.
On the roof, just outside the banquet area, a guest is demanding to be let in without a body check. Bege politely tells him they can't do that. The person, organ dealer Jigra, reminds Bege that he was invited to the last wedding too, but could not attend due to having to go to his mother's funeral. He told Big Mom this, and asks Bege to guess what she sent in return. Before he can finish, the man is shot in the head. Bege demands to know who shot him. A man on the doorframe then tells Bege how the story would have ended: "She sent me the head of my father, who was in the hospital. I'm here for revenge, open the door", at which point he would have opened fire, killing two of Bege's subordinates in the process. The person talking is revealed to be Sweet Commander Charlotte Katakuri, second son of the Charlotte Family, who had thrown a jelly bean at Jigra. Bege is visibly irritated by Katakuri's presence, given that Katakuri had trained his Kenbunshoku Haki so well that he can see slightly into the future, posing the biggest threat to Bege's plans. Katakuri instructs Bege to tell Big Mom that sniping Jigra was his judgment, before foretelling Bege's eventual acquiescence.
The final guests enter the party room, excited by the atmosphere. Charlotte Smoothie greets them and offers them a drink; the selection is a piece of lava, a beautiful woman who had stabbed one hundred men, and a giraffe that makes a funny sound. Giberson, Stussy, and Peclo all get a glass of the giraffe, squeezed into the glass by Smoothie's Devil Fruit ability. As they marvel at the taste and feel of the drink, Big Mom enters the venue. She welcomes the guests, informing them that everything in the room is edible and to make sure to enjoy everything that happens today.
- Aladine and the rest of the Sun Pirates leave Pekoms tied up and they prepare to leave the island as instructed by Jinbe.
- In addition to the amount of years taken, the numbers on the punishment roulette wheel indicates how many people would die should the one spinning it try to leave the crew.
- As Jinbe cannot deal with such unreasonable punishments, he decides to use the chaos during the Tea Party to escape from the island.
- Some Underworld figures are introduced.
- Sweet Commander Charlotte Katakuri is introduced.
- The tea party begins.