After leaving Battleship Island the Going Merry is now towards the Grand Line, and the crew now returns to the Great Adventure.

Upon entering the Grand Line, the ship is swallowed by a giant whale, inside of which they discover a strange place. In addition, they're not the only ones there.

Luffy and the others hear the story behind Laboon and his nakama.

As the Straw Hat Pirates travel from Reverse Mountain to Whiskey Peak, Nami has to adjust to the thought of having to watch the log pose constantly. As they arrive at their destination, the townspeople greet them warmly and throw a party in their honor. When the crew eventually falls asleep from exhaustion, the townspeople, who belong to the secret organization Baroque Works, plan on capturing them.

While Nami searches the town for the bounty hunters' treasures, Zoro lets loose on the bounty hunters the two new swords he received in Lougetown, Yubashiri and Sandai Kitetsu. Afterwards, a new threat arrives, the Baroque Works officer agents Mr. 5 and Miss Valentine. Their mission is to eliminate the traitors who know the true identity of the organization's boss, Mr. 0.

Mr. 5 and Miss Valentine follow after Vivi, who attempts to flee the island. Igaram, no longer in able to fight himself, begs Zoro to save her. When Zoro is about to take on Vivi's assailants, Luffy appears. Oblivious to the townsfolk's occupation as bounty hunters, he wants to kill Zoro for cutting them all up. Unable to convince Luffy of the truth, Zoro fights him.

Out of imminent danger, Vivi explains that Baroque Works is responsible for inciting a rebellion in her home country, which is why she cannot offer a large reward, and reveals that Mr. 0's true identity is the Sir Crocodile, one of the Seven Warlords of the Sea. Igaram sets out on the direct route to Alabasta, as a decoy. Miss All-Sunday, the partner of Mr. 0, appears on their ship. Without explaining her reasons, she offers the crew an Eternal Pose.

Coby and Helmeppo have enlisted into the navy and Coby works hard towards his goal of becoming an officer.

Coby and Helmeppo settle in at Marine headquarters, while Garp makes sure that they are not slacking off.