Over the course of its 13-episode first season, Fox's Sleepy Hollow has emerged as an unexpected hit thanks to its fast-moving mix of supernatural horror and police procedural. And each week, as the time-displaced Ichabod Crane (Tom Mison) has dug deeper into an apocalypse whose foundation was laid during the American Revolution, the audience's anchor in our world has been police Lt. Abbie Mills, played by Nicole Beharie.

Ahead of tonight’s two-part season finale, SPINOFF ONLINE took part in a call with Beharie to get her take on the drama’s most pressing matters, including the revelations about founding father George Washington's connection to the occult, the seemingly strained partnership between Ichabod and Abbie, and whether romance can be added to the show's genre DNA as the apocalypse looms.

"I think the show has hit the zeitgeist. It's just struck a nerve with a bunch of people," the actress said of Sleepy Hollow's breakout status. "The success of the show is about the audience. People are open and ready to take that kind of journey. They're looking for a fantastic but mysterious kind of drama. I think the show has a lot of different elements to it and demographics that open it up to a much broader audience. It is kind of outlandish. We're in danger. We're all over the place, and you never know which way it's going to turn. It's the audience's engagement with that and their coming along with the contract that makes the whole thing live."

The quick pace of world-building in the show inspired by Washington Irving's classic story has pushed Revolutionary War spy Ichabod Crane's modern-day face-off with the Headless Horseman – who’s actually Death, one of the Four Horsemen of the Apocalypse -- through multiple revelations. Beyond uncovering his own wife's role in an early-American witch coven, his former rival's reincarnation as the Horseman and the plans of an all-powerful demon called Moloch, the series has also spotlighted Abbie Mills’ familial connection to the supernatural forces running through the titular town. Beharie promised that the speed at which the story moves won't let up in the finale.

"We're being really coy. We can't give it away, but I think that's for the greater good. We can't get into the whole range of surprises, but I will say there are quite a few of them," she said. "John Noble is in the cast, and Victor Garber. The story starts off where Abbie and Crane unearth some secrets from the Bible – as you guys saw at the end of the last episode – and they discover some new things about the nature of George Washington's death. That sends them on this mad hunt, and that hunt tests their loyalties. There are sacrifices made."

Sleepy Hollow is already known for its high-caliber monster effects, and Beharie promises still more action for her character in the climax of the season, saying, "I had a massive fall I had to take, and I'd never done that before, so it was a lot of fun."

Meanwhile, viewers hooked on the mythological aspects of the show can expect a wrap that pushes the story forward into Season 2. "The finale in and of itself is a tease,” she said. “You have to watch it to see, but it's drastically different from where we started, where we're going. I don't think people will expect what we uncover."

One of the most pressing questions walking into the two-part episode is whether Ichabod might turn on Abbie as the demons circle. But Beharie seemed confident in the partnership despite the hints of a deepening rift between them. "I definitely think there are challenges along the way for every character,” she said. “In the last episode, you saw a little bit of questioning [of their bond], and in the episode where they captured the Horseman, they had their issues, but they are on the same side. I don't think that part has changes. But there are a lot of tests coming up, and with tests come those sort of challenges that measure the character's character – who they are, what they really stand for and how much they can withstand."

The actress also praised the show's ability to swerve away from straight thriller mode to give the characters some deeper shading. "There are so many different levels and dynamics. I think that it's an amazing gift for an actor to have an opportunity for tender moments in something that could be just procedural. And even when you follow the procedural, the next thing you know there's a supernatural element and then a conspiracy theory and then a history lesson. So it really works every muscle in your creative body."

And expectation-twisting is a piece of Sleepy Hollow that's been there from her introduction to co-star Mison. "I had only read the Washington Irving piece, and even though I read our pilot, that script didn't say that he'd be an attractive, tall Englishman. I thought he'd be kind of gangly and nerdy," she laughed. But Beharie said that fans "shipping" the two characters will be disappointed if they're looking for romance moving forward.

"I know that they have chemistry, and God only knows what happens in the future,” she said. “But I know Abbie, personally, isn't thinking that way. They have a massive job and a massive undertaking ahead of them. Trying to save the world is a pretty big deal. So trying to stay out of trouble is enough ... they move so fast on this show that by the time you blink or bat your lashes, there's something dragging you to the next portal of doom."

As for Abbie’s journey as a character, Beharie noted, "She's done so many things that she could never imagine and seen things in this world going on beneath our everyday lives. It's about understanding that what you knew is not all there is, and that's a huge theme in the show. She's basically given over to that now. She's cautious, but she's no longer cynical about what they're doing. She's committed to what they're doing, and it's all about serving that purpose. I feel like everything's changed."

She expressed the most satisfaction at being able to play against type explaining that early on producers encouraged her to "Keep it dry and have fun." Beharied said, "They gave me that path to make her what I want ... with girls on TV, they always want to sex it up. And I said, 'Look, she's gruff. She wants to get out of town. She's not too concerned about what anybody thinks because she's had a hard life.' And she's got secrets. I think it's great that everybody on the show has secrets, and in Season 1 we've only tripped some of that off. There's potential for a lot more there."

As to what could be uncovered in the finale and beyond, Beharie had to claim ignorance, as she's steered clear of too many spoilers herself. "They gave us an outline so we had the option to know where it was going, but I just basically asked for any information I needed to know that Abbie would have known – like when they were uncovering things from her own past. But as far as what was going to happen with each demonic entity or monster – each level of fighting the apocalypse – I didn't want to know all of it. I wanted to discover it as we moved along. And I think each writer brought something new, so even when we had an idea of what the next chapter would be, we'd have no clue of how it'd come to fruition."

Sleepy Hollow's season finale airs tonight at 8 ET/PT on Fox.