The Straw Hat pirates embark on a mission to Drum Island to seek medical attention for their ill crew member, Nami. However, they soon discover that the only doctor available is the reclusive Dr. Kureha, who resides at the peak of a treacherous mountain. Luffy and Sanji bravely take on the challenge and bring Nami along with them. Meanwhile, the return of Wapol, the island's former tyrannical king, and his brother threatens the safety of the locals. Wapol is the reason behind the shortage of doctors on the island and seeks to regain his power by turning the island into a dictatorship. The Straw Hat Crew meets new allies, such as Chopper Tony Tony, a half-human reindeer, and fights their way through obstacles to save Nami's life and prevent Wapol from wreaking havoc on Drum Island.