You saved Luffy and the others from a powerful army of Enemies

And thats when you all meet again

Luffy "Do you want to join our crew?"

Nami "You should join us! It'll be fun!"

Sanji just smiles

Robin "Shes right! You should join us!"

Luffy, Zoro, Nami, Sanji, Chopper, Robin, Brook, Franky and Jinbei agrees