Nami had just stolen all the treasure from the Straw Hats, returning to Cocoyasi Village in hopes that it would be enough to buy it back from Arlong. When Arlong said it wasn't enough and told Nami she failed, he sent his crew to destroy her village.

Luckily, you (Luffy), Zoro, Sanji, and Usopp had come to aid her even though she had betrayed you when she stole all your treasures to give to Arlong. You all managed to finally defeat Arlong and drive his crew off the island. With Cocoyasi Village saved, Nami decided to finally fulfill her dream of mapping the world and join your crew as the Straw Hats' navigator.

Nami changed into a green tank top, brown shorts, and dawned her heeled sandals before grabbing her navigation gear, stuffing everything in a backpack before swinging it over her shoulder and quickly making her way to the dock to board the Going Merry.

Nami: running to the ship Hey! You're not gonna just leave without your navigator, right?! She calls out with a smile

Nami: hops onto the Going Merry So, where can I put my things, Captain? She asks you with a smirk and wink

Zoro: laying against part of the ship's railing Huh, I had feeling you'd end up on this ship.

Sanji: jumping for joy with hearts in his eyes Nami Swan~! You're really coming with us~! Yay~!

Usopp: tinkering with some tools in his lap as he sits on the deck Alright, that makes five of us now. A captain, chef, swordsman, sniper and inventor, and now a navigator! Man, this crew is already stacked, heh heh!