Chapter 881 is titled "Wave Room".
The Stories of the Self-Proclaimed Straw Hat Grand Fleet Vol. 15: Sai Arc - "Don Sai and Baby 5's wedding"♡
Jinbe uses his skills as a helmsman to save the Thousand Sunny from Big Mom's wave homie by surfing inside its crest. The Big Mom Pirates believe that the Sunny was destroyed by the wave, but Luffy finds out the truth and promises to meet up with his crewmates even as Katakuri continues to attack him.
Luffy inquires what is going on aboard the Sunny as Big Mom and her wave homie close in. Charlotte Perospero tries to prevent her from striking the Sunny by telling her that she will also sink the supposedly stolen wedding cake, but his words fall on deaf ears. As the Straw Hats cry in despair, Jinbe instructs Chopper, Carrot, and Brook to adjust the main sail and asks Nami what direction the wind is blowing. Nami incredulously asks if he is going to steer the ship with just the main sail. Jinbe tells them all to hold on and he steers the ship into the 'Green Room', a short lived pocket made inside the crest of a wave. Nami stares in awe at Jinbe's skill as he pilots the Sunny out of danger.
Meanwhile in the Mirro-World, Luffy wonders if the Sunny has survived while Brûlée revels at the supposed destruction of the ship. Looking through the mirror to the Sunny, Joscarpone is curious as to why the ship does not appear to be underwater. As she states this, the mirrors begin to shatter with Mascarpone believing that it is due to the pressure the Sunny is experiencing underwater. Nami contacts Luffy through a mirror shard and asks him to get away from the others. He runs away, with only Katakuri noticing.
Luffy is notified that the Sunny survived and all the mirrors have been destroyed, per his orders. Nami notifies him that they are on their way to Cacao Island to meet up with Sanji, Pudding, and Chiffon, who are busy working on the replacement cake. Luffy is told to find a mirror that leads to Cacao Island after defeating Katakuri. Shortly afterwards, Katakuri traps Luffy with mochi and makes him fall, swallowing the shard. Katakuri then repeatedly kicks Luffy around and the latter narrowly escapes from getting smashed into the ground. After spitting out the pieces of glass, Luffy tells them to hurry. He struggles to stand up as Katakuri taunts him. Bringing his trident out from within his mochi, Katakuri predicts what Luffy will say and asks if he is certain he wants those to be his last words, with Luffy declaring regardless that he will not die here.
- Sai and Baby 5 are married.
- Thanks to Jinbe’s skill as a helmsman, the Thousand Sunny escapes destruction.
- The team on the Sunny breaks all the mirrors on the ship, preventing the Big Mom Pirates inside the Mirro-World from invading.
- The team on the Sunny tells Luffy to meet them at Cacao Island.