What Do The Red Lights In AHS: Double Feature Mean?

Season 10 of "American Horror Story" is subtitled "Double Feature" in reference to its division into two discreet parts (which, as teased in some early promos, may end up connecting). The first half of the season is called "Red Tide" — the "tide" portion of its title seemingly nods to its coastal Provincetown, Massachusetts location.

"Red Tide" stars Finn Wittrock as Harry Gardener, a screenwriter who moves to Provincetown upon the season's opening with his wife Doris (Lily Rabe) and daughter Alma (Ryan Kiera Armstrong). Soon after their arrival, Harry reveals to two patrons at a local restaurant — playwright Austin Sommers (Evan Peters) and romance fiction author Belle Noir (Sarah Cunningham) — that he's struggling to complete his latest screenplay. Austin ends up offering some black pills that he claims will push Harry past his creative difficulties.

So far, these black pills have proven key to the plot of "Red Tide." As Harry finds out, those who take the pills can tap into newfound artistic creativity, though the benefits can only be sustained by consuming raw blood. Furthermore, this is only possible in those with some level of existing talent. Non-creatives who take the pills transform into pale, braindead humanoids that wander the Provincetown streets. The nature of the Pale People is currently a source of speculation among fans who think there may be more to their character than what has been revealed thus far.

Another element of "Red Tide" some viewers have questioned is the significance of red lights that appear outside many Provincetown residents' homes come sundown — seemingly providing the "red" part of this half of the season's namesake. While there's no definitive answer to their function, fan speculation has provided a couple of probable theories.

Fans of "American Horror Story" gave a few possible answers about what function the red lights might provide in a thread on the series' subreddit, which asked users for theories about their purpose. User gafma suggested that the light indicates that its owner knows about the black pills and pale people. In that case, they would simply act as indicators of membership in a secret club of sorts.

The most upvoted comment, by user madame_hussain, pointed out that Belle Noir turns off her light after trading drugs to TB Karen (Sarah Paulson) for a living baby. Presuming this hints at the light's function, they suggest this might mean that each red light's owner is a black pill user searching for raw blood to sustain their habit. Thus, upon receiving a living human, Belle Noir turns off her light, indicating that's was no longer in need of a blood sacrifice.

User yakaroni suggested the very same in a similar thread also posted to the "American Horror Story" subreddit. Another user, papaya7777777, proposed that the lights might repel the Pale People but noted that this answer doesn't account for Belle turning hers off.

In each of these cases, the function of the red lights is intrinsically linked to the black pills. Furthermore, based on how many upvotes these theories received across the two Reddit threads, the fan consensus seems to be that a turned-on red light indicates its owner is in need of raw blood. More details about the red lights will likely surface as "American Horror Story: Double Feature" rounds out its season.