Windurst 2-1: Lost for Words
When you accept the mission from the guards at the gate, you have to head to the Optistery (Windurst Waters, F-5) and speak with Tosuka-Porika.
He wants you to find a book called the Book of the Gods. He thinks that Nanaa-Mihgo (popular cat burglar in Windurst) has it.
Speak with Nanaa-Mihgo (Windurst Woods, J-3) and she will give you the book if you get her a Lapis Coral. This involves going to the Maze of Shakhrami (most northern part of Tahrongi Canyon), which is invested with enemies. It is highly recommended you go with a party that can protect you or fight with you.
You can find the Lapis Coral on the rocks between H-4 and H-5. Once you have it, return to Nanaa and she will give you a key to her hide-out, which is in the Horutoto Ruins (East Sarubaruta, J-7), behind a Mahogany Door (G-8).
Once you get there, a cut scene occurs in which Nanaa and her friends are threatening you. Right before things get ugly, Ajido-Marujido comes to your rescue (not in a very heroic way, either). Follow him to the House of the Hero (Windurst Walls, G-3) and the book is found. After speaking with him, travel back to the Optisery (Windurst Waters, F-5) and speak with Tosuka to complete the mission
Next: Windurst Mission 2-2