The first Red Letter is found behind the Red Door in The Underpass, leading to the Inner Sanctum, where the lever to Room 46 is found. To open the door, you need to power the red box in the Boiler ...

If you buy something from an Eater link, Vox Media may earn a commission. See our ethics policy. Francky Knapp is the commerce writer at Eater, and an award-winning writer with bylines in GQ, VICE ...