Nami form an alliance becoming the navigator of the crew, but not a full member yet. They arrive in Syrup Village looking for a suitable ship. On this island they know the liar Usopp, who also has ties to the Shanx.

When trying to convince his rich friend, Kaya, to give the Straw Hats a ship, Usopp is told to stay away from her by her caretaker, Klahadore. However, when Usopp and Luffy later see him conversing with a strange man, they learn of a plot to kill Kaya.

After learning of Captain Kuro's evil plan, Usopp runs back to the village to warn Kaya, only to find that after all his years of lying no one believes him.

Usopp resolves to keep his story of pirates attacking the town a lie by making sure none reach it. Luffy, Zoro, Nami, and Usopp then try to keep the Black Cat Pirates at bay.

The Straw Hats manage to take out most of the opposing Black Cat Pirates, so Jango orders the Nyaban Brothers to attack. Meanwhile, after getting hypnotized by Jango, Luffy gets himself stuck under the collapsed mast of the Black Cat Pirates' ship.

Captain Kuro himself arrives at the scene, and with Zoro too injured to fight, Luffy being incapacitated, and the other two being too weak to handle him, things seem hopeless. However, Kaya herself appears to bargain with Kuro.

Zoro and Buchi (of the Nyaban Brothers) face off once again as Luffy and Kuro begin their fight. Usopp orders the Usopp Pirates to run away with Kaya, but Jango goes after them. A flashback reveals how Captain Kuro faked his death with Captain Morgan and how he became Kaya's butler.

As the fight between Luffy and Kuro is close to an end, the Usopp Pirates do their best to avoid Jango.

Kuro's ultimate attack, "Shakushi", attacks everything in the area, whether friend or foe, and Luffy becomes enraged by his lack of regard for his crew. Will Luffy's determination overcome Kuro's sheer speed?

With Usopp now in the crew and a new ship, the Going Merry, under their command, the Straw Hats head to an island said to hold a fabled treasure, only to encounter a strange man stuck in a treasure box that has also been looking for this treasure.