After helping Zoro escape, Nami is accused of treason by Arlong's officers. To prove her allegiance, she stabs Usopp in the stomach, causing him to fall into the pool.
Luffy, Sanji, and Yosaku finally reach the island with the help of the sea cow, Momoo, but their arrival is chaotic as their ship crashes into the forest, where they reunite with Zoro.
Watch a breakdown and reaction to the shocking events of Nami's apparent betrayal in this episode: