Originally developed as a feature film adaptation, the idea was re-imagined as a television series for Netflix when the service had given the production a series order for a first season. Filming takes place in multiple locations in Andalusia Spain, such as Antequera, where the headquarters of the fictional Order of the Cruciform Sword was filmed.
The series is narrated and led by Portuguese actress Alba Baptista in the role of Ava Silva, a tetraplegic orphan who discovers she now has supernatural powers which force her to join an ancient order of warrior nuns. The series marks Baptista’s English-language debut. The cast also features Toya Turner, Thekla Reuten, Lorena Andrea, Kristina Tonteri-Young and Tristan Ulloa.
After waking up in a morgue, an orphaned teen discovers she now possesses superpowers as the chosen Halo-Bearer for a secret sect of demon-hunting nuns.