Rebel Warrior Koza! The Dream Sworn to Vivi!

The crew, joined by Vivi and Ace, press on through the sand toward the oasis town of Yuba, where Vivi means to find the rebel forces. As Luffy, Usopp, and Sanji squabble over the dwindling water in a skin bottle, Nami asks Vivi to say more about the uprising, and Vivi begins a tale set eleven years in the past.

In that memory, a young Koza storms before King Cobra, furious that his drought-stricken village has gone without aid. The king answers that the rains lie beyond any ruler's command, then quietly promises to care for the suffering village. Koza's father Toto arrives mortified, begging to bear his son's punishment, but Cobra waves it off, remarking that the boy's anger springs from genuine love for the people.

The young Vivi tracks Koza down and challenges him for leadership of the Sand-Sand Clan. After their scuffle, Koza names her the group's assistant leader, and she grows close to his family. Watching from hiding, Cobra is pleased that his daughter is making the friends a future ruler will need.

When kidnappers target Vivi, the clan children rally to shield her, and Koza takes a sword cut near his eye protecting her before Igaram, Cobra, Pell, and Chaka arrive to crush the abductors. A tearful Vivi pleads with Koza never to risk his life for hers again. Soon after, Koza departs with his father to help rebuild Yuba into a town, urging Vivi to grow into a great princess.

Back in the present, Nami praises Koza as a decent person and asks how he connects to the rebels, prompting Vivi to reveal that her old friend now commands the rebel army. The episode belongs to the Arabasta Arc.

The anime shifts the timing of the flashback so that Vivi tells the story on the road to Yuba rather than after arriving. It also alters small details: the children never notice Cobra and Igaram spying on them, and Vivi bites the third kidnapper's finger before fleeing, a moment not in the manga.