Apple TV has greenlit the horror thriller series “Ascension” from Alfonso Cuarón with Caitríona Balfe attached to play the lead role, Variety has learned.

Cuarón has been working on the series for years, with word of it first breaking in 2017 with Casey Affleck originally attached to star. It is inspired by the novel “Last Days” by Adam Nevill.

The logline for the show states that it follows Rose (Balfe), “a relentless documentary filmmaker and recently divorced mother, brilliant at uncovering others’ truths but struggling to resolve her own. When Rose begins a project on a mysterious 20th-century cult known as the Church of Ascension, she finds unexpected refuge in its teachings – until she discovers something far more insidious beneath.”

Alfonso Cuarón is co-writer on the series along with his brother Carlos Cuarón as well as Natalie Erika James (“Apartment 7A,” “Relic”) and Christian White (“Apartment 7A,” “Relic”), with all four executive producing. James and White also serve as co-showrunners, with James serving as lead director. Balfe will executive produce in addition to starring. Alfonso executive produces under his Esperanto Filmoj banner, which has an overall TV deal with Apple.