Chapter 847 is titled "Luffy and Big Mom".
Meanwhile, Big Mom takes the Vinsmoke Family to her library, where her son Mont-d'Or captures many kinds of humanoids and beasts inside of books. Vinsmoke Judge asks why he has not seen any giants in Totto Land, causing Big Mom to briefly become enraged before excusing herself to attend to other matters. She then contacts Luffy and Nami, who are trapped within another book, with a Den Den Mushi. Luffy maintains his determination to rescue Sanji and defeat Big Mom, but Big Mom asks about Lola, whom Nami explains that they are friends with. However, Big Mom reveals that she thinks little of Lola, as she ran away from a political marriage that would have enabled her to defeat the other Four Emperors and allowed her to become the Pirate King. Big Mom wants Nami to tell her Lola's location, but Luffy continues challenging her.
Meanwhile, Sanji sits by a window, hoping the best for his crewmates. In the Room of Treasure, Pedro creates a distraction, and Brook prepares to unleash a special concert while the mink covers for him.
In Brûlée's house in the Mirro-World, Carrot cries for help as Brûlée lowers her into a hot cauldron. The homies nearby look forward to eating rabbit mink meat, and a chained-up Chopper retorts that Carrot does not even taste like rabbit. Brûlée quiets him, saying he would join Big Mom's collection of strange beasts. However, since Chopper is in Heavy Point, he knows he can escape from his chains simply by transforming, and can also use Monster Point again if needed. As Carrot gets closer to the cooking pot, Chopper prepares to take the chance to escape and fight.
Meanwhile, Big Mom takes the Vinsmoke Family (minus Sanji) to the library in the Whole Cake Chateau. She opens a very large book, revealing a manticore that had escaped from Impel Down two years ago inside a page. She then shows them a unicorn, and the Vinsmokes are intrigued to see living creatures within the pages of a book. Big Mom reveals that the library is full of a large range of creatures that never age, kept within books by her son Mont-d'Or's ability. She says that her most recent additions include a centaur from Punk Hazard, a griffin from the South Blue, and a longarm-longleg hybrid known as a longlimb human. Niji is shocked that she keeps humans in the books as well, and Judge notes to Big Mom the large diversity he has seen in Totto Land. However, he says that he has not seen any giants, and Big Mom's expression turns sour and angry, but she quickly returns to her normal self and replies that he probably just missed them. A servant then reports to Big Mom that they have brought the two she asked for, and Big Mom takes her leave from the Vinsmokes. She asks her servant why he is acting nervous, and he expresses his admiration for the Vinsmokes, and Big Mom tells him to be quiet and not place so much worth on what is on the outside.
Meanwhile, in the Prisoner Library, Mont-d'Or, Bobbin, Perospero, Opera, and Galette turn a book to page 55, where Luffy and Nami are being kept in a cell. Big Mom's Den Den Mushi is then placed in front of the two Straw Hats, and Luffy shouts at her to let him go. Big Mom laughs at his liveliness and says that she thought he had broken his promise to battle her due to not bringing his entire crew. Luffy replies that he still intends to fulfill that promise, but now he is just here to get Sanji back, though he would still fight Big Mom if she showed up. Big Mom and her subordinates outside laugh at the statement, with Big Mom telling Luffy that he was nothing compared to her and that she could have him killed without even needing to show up. Big Mom says that if they give up on rescuing Sanji, she will free them once the wedding is complete, as the wedding is the most important thing to her right now. However, she tells the Straw Hats that if they interfere with her plans, they should get ready to see hell. Big Mom recalls the time Luffy ate her candy on Fish-Man Island and gave her treasure in return, revealing to him that a legendary treasure box known as the Tamatebako was a part of it. Big Mom wonders why Fish-Man Island gave away a national treasure, but has taken such a liking to the box that she will forgive the Fish-Man Island incident altogether and open the Tamatebako in front of everyone during the wedding ceremony.
Luffy shouts at her to be quiet, saying the wedding would not happen and asking to speak to his friend Pudding. Big Mom laughs incredulously about the Straw Hats being friends with the bride-to-be, and asks Nami if she really killed Lola like she had heard. Nami vehemently denies it, saying that they were friends with Lola and she had given them Big Mom's Vivre Card, having told them to tell Big Mom she was well and that the Vivre Card would cause Big Mom to help them out. However, Big Mom quiets Nami in a fit of rage, saying in great anger that she would like very much for Lola to be dead and will send hired assassins after her if Nami reveals her location. Big Mom reveals that Lola ran away from her most crucial political marriage of all time, and that she would never forgive her. Nami is shocked as she remembers meeting Lola on Thriller Bark and how Lola wanted to marry every man she met, and Big Mom shouts that were it not for Lola's rebellion, she would have gained enough power to defeat Kaidou, Shanks, and even Whitebeard and become the Pirate King. Big Mom says that she will get Lola's location out of Nami eventually, but Luffy shouts that her story is boring, saying that Lola did not need to be a pawn in Big Mom's rise to power. He challenges the Emperor again, saying he would get Sanji back and defeat her in the end.
Meanwhile, inside a guest room, Sanji sits on a windowsill with his head in his hands, hoping his crewmates stay safe and do not do anything rash. Inside the Room of Treasure, Tamago and a Chess Soldier race to intercept Pedro, who is causing trouble out in the open. While Pedro distracts everyone, Brook prepares to give a special live concert.
- Brûlée has captured both Chopper and Carrot.
- The last silhouetted figure from Chapter 827 is seen with Brûlée, although no name is given.
- Big Mom has a collection of rare creatures stored inside books.
- Her collection includes a unicorn, a griffin, a centaur from Punk Hazard, some species of panda, and a manticore.
- Charlotte Mont-d'Or's ability lets him store people and objects in the pages of books.
- A hybrid of the Longarm Tribe and the Longleg Tribe is mentioned and they are called longlimb humans.
- Judge points out that there are no giants seen in Totto Land, and Big Mom is briefly enraged when she hears the word.
- Big Mom plans to open the Tamatebako during the wedding.
- Luffy and Nami are held prisoner inside Big Mom’s castle.
- It is revealed that Charlotte Linlin is angry at Lola, because the latter escaped from an important political marriage that would have enabled the former to become the Pirate King.
- Brook and Pedro begin their plan to acquire the poneglyphs.