One Piece Episode 591 English Dubbed Episode Title:Chopper Enraged - Master's Inhumane ExperimentsEpisode Description:The children and the Straw Hat Pirates 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. The children then start to fall over in pain while asking for candy. Chopper, who had been testing them for any sickness, reveals that they had been given a highly addictive drug and are suffering from withdrawal. The children then attack the Straw Hats, who could not fight back without injuring the children, and eventually Usopp uses his Bakusui Boshi attack to put them to sleep.