Zephyr, now called Z, has a singular mission: obliterate all pirates and their aspirations of becoming King of Pirates. When Luffy and his crew cross paths with him, they suffer a crushing defeat at the hands of Z, who wields a Seastone arm. The stakes rise as Nami, Robin, and Chopper are mysteriously de-aged by Z's ally, Ain. Fueled by a fierce determination to avenge their loss, Luffy becomes blind to Z's destructive scheme that threatens countless lives, putting both his crew and the world in jeopardy.