When TVLine was approached about chatting with Kate Siegel about The Haunting of Bly Manor, it was under the agreement that we wouldn’t breathe a word about the conversation until today, three days after after the horror anthology’s second season premiered.

After all, Siegel — who played The Haunting of Hill House‘s touch-y psychic Theo — doesn’t show up until Bly Manor‘s penultimate episode (most of which was shot in black-and-white), and details about her character were kept under tight wraps during filming. And with good reason: Siegel’s Viola, a 17th century woman whose sister kills her in her sleep, turns out to be the very reason that the British country estate is haunted by the spirits of anyone who has the misfortune to die there.

Though much of Bly Manor is based on Henry James’ novella The Turn of the Screw, series creator Mike Flanagan also pulled heavily from James’ The Romance of Certain Old Clothes, which provides the bulk of Viola’s narrative (albeit with a few tweaks). But little of this was known before the season hit Netflix Friday.

So when we talked to Siegel ahead of Bly Manor‘s premiere, we sensed joy in the very act of her being able to discuss the show in detail, starting with that commanding painting of her as Viola that hangs in the home’s magnificent entryway throughout the season.

Q&A with actor Kate Siegel on The Haunting of Bly Manor. Moderated by Mara Webster for In Creative Company.

Spoiler alert, Haunting fans! If you have not already binged The Haunting of Bly Manor on Netflix, leave now because we’re chatting with the most mysterious star of the season…

The eighth episode of Netflix’s “The Haunting of Bly Manor” is a very different installment from the rest, shot almost entirely in black and white and told almost exclusively via the show’s nameless narrator, played by Carla Gugino. And the reason for such a drastic difference between this hour, the penultimate of the season, and those that came before it is because here is where we finally go back in time to learn the story of how Bly Manor became haunted in the first place. It’s a tale of two sisters, Viola (played by Kate Siegel) and Perdita (Katie Parker), and how their intense love for one another killed them both and turned Viola into the Lady in the Lake who haunts Bly Manor.

“It’s sort of experimental. And it takes you away from everybody you love,” Siegel told TheWrap of the episode, titled “The Romance of Certain Old Clothes.” “But in that moment, it puts in me, who plays Theo [in ‘The Haunting of Hill House], who everyone is waiting to see, and it draws you in immediately. And so you don’t have that moment of, ‘What? Where am I? I don’t want to do this. I don’t care.’ You’re like, ‘Oh, there’s Kate! I’ve been waiting.’ Because you knew I was in the show, but nobody up until launch knew what I was in the show. There was none of me in the trailer. I was not allowed to say anything in the press. I wasn’t allowed to say anything on socials. So in that moment when they freeze on my face with [fellow ‘Hill House’ alum] Katie Parker… there’s that moment where you’re jolted out of your comfort zone, but you’re also sucked in by familiar faces.”

Every ghost has a backstory; it’s maybe the most important thing about them. Netflix’s The Haunting of Bly Manor is loosely based on Henry James’ novella The Turn of the Screw, much as its predecessor The Haunting of Hill House was loosely based on the Shirley Jackson novel of the same name. But that’s not the only James story that the new season is riffing on. Another one, titled “The Romance of Certain Old Clothes,” is the source for both the title and story of episode 8 of Bly Manor, which stands apart from the rest in several ways. Filmed in black-and-white and set centuries before the rest of the season’s episodes, “The Romance of Certain Old Clothes” is essentially an origin story for how Bly Manor first came to be haunted by vengeful ghosts. It stars Hill House alums Kate Siegel and Katie Parker as Viola and Perdita, two rich sisters who end up competing for the love of the same man and killing each other, eventually becoming two of the house’s first specters: The Lady in the Lake and the faceless spirit crawling around the attic, respectively.

Siegel is married to Haunting showrunner Mike Flanagan, and the two frequently collaborate on his film and TV projects. Siegel starred in Hush, Flanagan’s 2016 Netflix horror film about a deaf woman being stalked by a killer in her home, and had a major role in The Haunting of Hill House as Theo Crain. Her role in Bly Manor is more limited but very impactful, so EW caught up with Siegel to discuss filming in black-and-white and the particular resonance of haunted-house stories in a year that so many of us have spent cooped up indoors.

[Warning: The below contains MAJOR spoilers for The Haunting of Bly Manor.]

The Haunting of Bly Manor — an atmospheric, 1980s-set gothic romance, brimming with ghosts of all kinds — dropped on Netflix last week, to the delight of horror fans everywhere.

The series, inspired by author Henry James’ classic story “The Turn of the Screw,” follows au pair Dani Clayton (Victoria Pedretti) who is hired to watch over Bly Manor’s orphaned children, Flora (Amelie Bea Smith) and Miles Wingrave (Benjamin Evan Ainsworth), in the English countryside. During Dani’s time at Bly, she is challenged by her inconsistent charges, as well as the sinister happenings she sees on the grounds. In Episode 8, “The Romance of Certain Old Clothes,” viewers learn the origins of Bly’s ghosts (particularly the elusive Lady in the Lake) in a black and white fairytale-like flashback that tells the story of the Willoughby sisters who lived in the house long before it became the Wingraves’ summer house. The tragedy that befalls siblings Viola (Kate Siegel) and Perdita (Katie Parker) when the former, also the head of Bly, takes ill, is an emotional tale, but it also explains the origins for nearly all of Bly’s other ghosts (with the exception of T’Nia Miller’s Mrs. Grose) from the witch doctor to the faceless child Flora sees in her room.

These other ghosts were all created by Viola’s spirit, which haunts Bly as the Lady in the Lake, as she carves a pathway through the house to her bed, seeking out her long-gone child, and taking down anyone in her path. She nearly gets Flora, too, but in a harrowing moment near the end of the season, Dani volunteers to host Viola’s spirit inside her own body, and carries the looming threat away from Bly once and for all.

Below, Siegel, who also played psychic middle child Theo in the anthology’s first installment, The Haunting of Hill House, explains her thoughts on Viola’s “love story,” and the inspirations behind the feminist tale.