The Secret of (REDACTED)

The Secret of [REDACTED] is a single-stage overseer quest in Fallout Shelter.

Walkthrough
You are sent to a vault to find out about some great conspiracy, and will meet very secretive settlers. However, in this standard randomized vault, they will not be hostile if you choose the correct speech options (see below). In the second room you will meet the first group, then fight your way against multiple creatures such as radscorpions, molerats, or deathclaws, to reach the other two rooms containing information about a conspiracy going on that will probably blow your mind.

Behind the scenes
The mentions of "23 skidoo" and "Discordia" as well as the overall theme of conspiracy are probably a reference to the religion of Discordianism and The Illuminatus! Trilogy which is a series of novels exploring said religion.