One Piece: Defeat the Pirate Ganzack! is a oVA anime that premiered in summer 1998, produced by Production I.G.

About the production: the story comes from a manga, there is 1 episode of about 28 minutes and its current status is "finished".

Its main genres are adventure, comedy and fantasy, with themes such as Shounen, Pirates, Male Protagonist and Ships.

On AniList, One Piece: Defeat the Pirate Ganzack! has an average score of 65%, a good score, and appears on 13,722 users' lists.

While Luffy and his crew of Zoro and Nami are starving on their small boat, they are attacked by a large monster. Nami is taken away, while Luffy and Zoro wash up on shore. There they meet a young girl, Medaka, and learn of the sad history of the island. The evil Pirate Ganzack has taken away all the men in the village and enslaved them, including Medaka's father. Now Luffy, Zoro, and Medaka must infiltrate Ganzack's base in order to rescue the villagers and Nami. (Source: Anime News Network)

Official synopsis from AniList.