Confirmed by Redon
Detailed summary-
Chapter 997 title: "Homura (Fireworks)"
In the cover we can see Sanji trying to meditate in a temple, but he's getting distracted by Nami playing volleyball outside. A tanuki monk wielding 3 swords, is hitting him.
-The sounds Sanji heard was from 2 of Black Maria's subordinates, it was all an act to lure Sanji into a trap. Sanji gets caught in a spider's web, he's surrounded by Black Maria and her subordinates who look like Japanese demons.
-2 new Shinuchi are blocking the stairway between 3rd and 4th floor. They are Poker, a rattlesnake Smile user and Mizerka a girl user of the gorilla Smile (both have cool designs). The samurai make a hole between floors and make a ladder for Luffy and Jinbe to climb up directly to 4th floor. Poker and Mizerka are ignored.
-Big Mom flies up to the roof through the hole Kaidou made when he flew up to the top floor of Onigashima.
-In the main stage, Zoro notices something is falling down. It's Kiku's arm. Then Zoro decides to get serious. He walks to Apoo, who's busy fighting X Drake, and defeats him using the Ittouryuu (one sword style) .
-Zoro gives the antibody to Chopper and leaves the floor to him. Chopper announces that the virus is fused with gas that cools the body down. If infected people warm their body up with fire, the virus will stop spreading.
-Chopper tells everyone to warm up their bodies while he makes the antidote. He will cure everyone, including the enemies. Queen is about to shoot Chopper with his bazooka but Zoro sends a shockwave from his sword and destroys the bazooka.
-Zoro: "I'm not here to play your games! I'm here to cut down Kaidou, the strongest guy in the world!!"
-Suddenly the whole Onigashima island starts shaking. Brook thinks if it's Zoro's Haki and if he’s using Haoshoku Haki, but it's not. Zoro tries to find a way to go up but King and Queen are still guarding the hole in the ceiling. Marco flies into the room and offers help.
-Cut to everyone on the island reacting to the earthquake. Heart Pirates try to join the fight but because of the quake, their submarine cannot get close to Onigashima island.
-Cut to Yamato, she's taking Momonosuke to the port. Yamato says Momonosuke's life is very important for Wanokuni, so she will help him to leave the island. However when they reach the port there's no ships... and no sea.
-We finally discover why the island is shaking. Kaidou used "Homuragumo" (Flaming Cloud) to lift up the entire Onigashima to the sky. Then he flies it to the Flower Capital in Wanokuni. At the end of the chapter we can see Kaidou standing alone…
Kaidou: "Let's begin the "world of violence"!!"