Once Ryan Murphy revealed all the American Horror Story seasons were connected through the same shared universe, fans started piecing together the overarching timeline to discover how the events of one installment line up with the rest. This was all going swimmingly until Apocalypse, when the seeming end of the world happened BEFORE events we had already seen taking place in a world that very much existed. The extensive flashbacks this season (including flashbacks within flashbacks) further convolute the timeline, which results in headaches for anyone who tries to piece the storylines together. So let me quickly break it down for you:
2012: Michael Langdon (Cody Fern) is born.
2015: Michael leaves the Murder House to be with the Satanists.
2020. The apocalypse goes down.
2021: Michael arrives at Outpost 3, kills everyone and the witches show up.
So how did Billie Dean attend Devil's Night at the Hotel Cortez in 2022 if the Antichrist had already set off the nuclear apocalypse in 2020? We might actually have an answer for you, and it's tied to another of the big mysteries this season: Mallory (Billie Lourd).
Mallory has been clearly marked as Important since her run-in with Michael during the interview process in Episode 3. But what really piqued interest in her regarding the timeline confusion didn't come until Episode 5 when Myrtle (Frances Conroy) saw Mallory not only resurrect a dead deer, but turn it into a young fawn. It was as if Mallory was able to reverse time for the deer, undoing its wounds and its aging. That instantly set off major foreshadowing alarm bells, leading many to think that if Mallory's powers develop enough, she could potentially turn back time on a larger scale, reversing the events of Michael's apocalypse and therefore saving the world.
The idea of this entire season eventually being reversed does feel like an easy cop out, but it would solve the continuity error within the Hotel epilogue. Lending more credibility to this theory is the fact that the final image of Apocalypse's opening credits is a shot of a candle going out in reverse, so clearly the theme of reversing events is woven throughout the season, whether it's as literal as this theory suggests or not.
The fandom seems to be split about what this could mean for Mallory and what she truly is. Some suggest she'd have to be the next Supreme to have that sort of power, while others wonder if she's the second coming of Christ. There are others still who believe she may be an angel or even just an extremely powerful but otherwise normal witch. Whatever she is, it does seem highly likely that Mallory will be the key to reversing the events of this season or, at the very least, using her powers demonstrated in the deer incident to stop Michael.
As Reddit user ccaelesti pointed out, Mallory's powers in resurrecting the deer were mirrored in Michael's powers in killing the Murder House owners in Episode 6. The pair appear to be the yin and yang of each other, with Michael's abilities bringing about destruction and Mallory's bringing about life. The same mirroring of their abilities can be seen in how Constance (Jessica Lange) tried to cover up the deaths of animals at Michael's hands under her rosebushes, while Mallory created life from a rose when she turned one into butterflies.
In nearly every way, Mallory and Michael appear to be the inverse of one another. This dynamic gives even more credence to the idea that it will be Mallory who has to recreate the world after Michael destroyed it, whether that's by reversing the timeline -- which would solve a lot of continuity errors -- or by building a new world out of the rubble. But unless this new world also includes a footnote about how Billie Dean and the Hotel Cortez survived the apocalypse, we're going to bet our money on the timeline reversal.
American Horror Story: Apocalypse airs Wednesdays at 10/9c on FX.