This is located in the last big area before the exit to Titan Robot Production Plant. There’s a spot where you can go to a lower area, with two oxygen-filled rooms, one smaller than the other. The symbol is on the wall to the left of the smaller room’s entrance, which will also become the entrance to Sub-Level 13.
Taking place between the events of Borderlands 1 and Borderlands 2, The Pre-Sequel details the events of how Handsome Jack became what he was during the second game. You play as one of four new character classes as you explore the moon of Pandora, Elpis, jumping around in low gravity, collecting all new loot and just shooting everything and anything you find!
Inside you will find:
A complete walkthrough of all main story missions and all of the optional missions;
A guide to complete all of the location-based Challenges;
How to get every single Achievement and Trophy;
Maps, images and locations of all of the Vault Symbols.