(or is it?)
Today we visit the stage right after Carreaux Theater, Trefles Library.
Overall, the stage is fairly straightforward and does not contain too many hidden secrets like in Theater, so this guide will be relatively short.
Here is the Video Walkthrough: https://youtu.be/AMjSY97YIFU
Below is a text-based Walkthrough that shows all key items you can acquire from this map, which is all covered in the above video but is provided for convenient reference.
The recommended comp for clearing this floor is SK/Phoenix/VC, with a LE friend. However, you are free to use whatever comp you like as there are no particularly difficult enemies.
The floor plans for the library is as follows:
First, accept the quests from Questgivers 1 and 2, then, visit each Quest location to complete them (Note that you must clear these quests to remove the Questgivers, thus giving you access to the items blocked by them).
Questgiver 1 provides you with a “remote” that allows you to clear all Quest 1 blocks. You should retrieve it first.
The quest located at (11, 9) appears to be an empty tile, but stepping on it will give you an item.
Floor 3 has a very similar layout to Floor 1, and Questgiver 1 will ask you to re-flip the shelves you flipped from Floor 1. These are marked as Quest 1 on the floor plan.