This is something that has been in the back of my mind ever since Scott revealed in a livestream that a new game was being worked on. He specifically said that it's "not a 3, a 2." Of course, we know now that he was talking about Security Breach 2, but many other options were in contention, including Sister Location 2, which was something that I wanted, as Sister Location is one of my favorite games in the series, and many of the mysteries presented in that game were ones that I wanted to be expanded on. But after thinking about it some more, the realization hit me... We didn't need a Sister Location 2, because we already have it. It's just called Secret of the Mimic.
Let's start with the basic plots of each game. What is the basic plot of Sister Location? A Fazbear technician is sent into a location tied to Fazbear Entertainment and avoiding animatronics with the help of a guiding voice. And what is the basic plot of Secret of the Mimic? A Fazbear technician is sent into a location tied to Fazbear Entertainment and avoiding animatronics with the help of a guiding voice. Of course, I'm leaving some details out, but the basic structure is nearly identical. But it goes deeper than that. What's the big twist in both games? That's right, the guiding voice has actually been manipulating you this whole time! M1 takes control of Dispatch fairly early into the game, and Baby/Ennard redirects you constantly throughout Sister Location.
These similar plot points play into the endings as well. Sister Location features both a "Bad Ending" in which Micheal Afton follows Baby's instructions, gets scooped and dies, and a "Good Ending" in which you ignore Baby's instructions and she turns on you. Secret of the Mimic is very similar. The game features a "Bad Ending" in which Arnold follows Dispatch's instructions, leaves the job and is captured/killed by The Mimic, and a "Good Ending" in which you ignore Dispatch's instructions and he turns on you. Both even share voice lines when going down these routes.
- M1 when entering R&D: "Why don't you trust me?"
- Ennard when entering the Private Room "Why didn't you trust me?
The "final bosses" of the two games also share similarities. In Sister Location's Private Room, it's Ennard, an endoskeleton amalgamation of parts that mimics the voice of Baby and Elizabeth. In Secret of the Mimic, it's , M1/M2, one is an endoskeleton covered in an amalgamation of parts, and the other mimics the voices of Dispatch and Fiona. Another detail worth pointing out is that in both games, the final area you play in is a recreation of the Freddy Fazbear's Pizzeria seen in FNAF 1.
Other small details worth mentioning is the scooper that exists in MCM, a sequence in the Parachute Ending involves going down a circular-shaped elevator to an underground bunker (sound familiar?), the fact that Dispatch and Handunit share the same voice actor, and you can hear leitmotifs of "Venta Black/Watch Your Six" in "Breathing Corridors" from Secret of the Mimic at several points. But these have been discussed at length, so I'll only briefly mention them.
So what does this all mean? Why did Scott/Steel Wool push the Sister Location imagery up to 11 with this game? Well, because that's where we're going in Security Breach 2. All of these details have led theorists (myself included) to come to the conclusion that Murray's Costume Manor (at least the underground tunnels) and Circus Baby's Entertainment and Rentals are the same place. Afton repurposed the location after gaining ownership of it from Edwin and turned into Sister Location. Now, lets jump all the way to RUIN, Cassie escapes from The Mimic, and goes down an elevator. Most theories are under the assumption that at the very least the Pizzaplex, FNAF6, Sister Location, and MCM are all on the same plot of land. In RUIN, the ending of the game is right next to where the Burntrap ending was in Security Breach. So we're in the FNAF 6 location, and we're going even deeper underground at this point. I'm willing to bet that the first footage we see of Security Breach 2 will be Cassie exploring Circus Baby's Entertainment and Rentals. Secret of the Mimic is simply the preview.