Worst of the World - The Scary Scientist Caesar

G-5 discusses the possibilities of Caesar Clown being behind the unusual events at the island. Brownbeard briefs Luffy about an incident that took place two years ago. Smoker reveals Caesar's true intentions.

Chopper Enraged Master's Tyrannical Experiments

The children and the Straw Hats are in a cave with Brownbeard tied up talking about the Master. Zoro, Sanji and Brook go to look for Kin'emon, who had gone to look for his torso that Brook saw roll towards the ocean. The children start complaining and falling over from pain. Chopper, who had been testing them for any sicknesses, revealed that they had been given a highly addictive drug and were suffering from withdrawal symptoms. The children start attacking the Straw Hats, who can't fight back without injuring the children. Usopp eventually is able to put them to sleep with one of his new attacks. Back in the lab, Law gave Smoker's heart to Caesar, who had sent the Yeti Cool Brothers to deal with the Straw Hats. The Yeti Cool Brothers are then shown talking to each other while Zoro, Sanji and Brook were lying unconscious nearby.

Gang Obliteration! Legendary Hitmen Attack!

The Yeti Cool Brothers are making their way to the destroyed lab where the Straw Hats and the children are. Monet tells Caesar about Law having some relation to Luffy, which makes Caesar mistrust Law until Law reassures him. The Yeti Cool Brothers then attack the cave and shoot Brownbeard. They take Nami (Franky's body) with them. Luffy arrives and attempts to rescue Nami but fails. Law is challenged by two of Caesar's men as he leaves, and is forced to attack them.

Save Nami! Luffy's Snow Mountain Battle

Chopper tells the others that Nami in Franky was kidnapped by the Yeti Cool Brothers. Franky in Chopper takes a rumble ball and becomes unconscious, Luffy and Franky go after the Yeti Cool Brothers to save Nami and defeat them. Meanwhile, Caesar notices Vegapunk's beam in Franky's body and craves for it, he calls his men so they go to the fire side gate and see a cave. Luffy and the Yeti Cool Brothers fight and by the end Law appears and defeats them. Law then propsoses an alliance to take down a Yonko to survive in the New World.

Formation! The Pirate Alliance Luffy-Law!

Luffy and Law agree on an alliance; the rest of the Straw Hats disapprove while Robin approves, even if she warns Luffy about a possible betrayal in a pirate alliance. Law switches Nami , Franky and Chopper's bodies again. Nami ends up in Sanji's body because Sanji is far away with Zoro and Brook . Law tells them that they can't go back once things start moving for example capturing Caesar Clown who has the Logia type Gasu Gasu no Mi. He warns them that he is highly dangerous therefore, they need Haki users to beat him. Luffy says that the Haki users there are him, Law, Zoro and Sanji. The marines are continuing their fight against Caesar's men. The three centaurs open the door and see a big glop of Slime that seeps out poison gas, most of them die and two survive so they run as it chases them. Caesar calls the pet slime monster Smiley and says that the Straw Hats and the G-5 marines are being used as test subjects for it.