The series centers on Ava Silva (Alba Baptista), a young woman who wakes up in a morgue with a new lease on life after a near-death experience. She discovers that she has been chosen to become a “Warrior Nun,” a member of an ancient order of nuns who fight demons and protect humanity from supernatural threats. Ava inherits a powerful artifact—a halo—embedded in her back that grants her extraordinary abilities.

As Ava adjusts to her new role, she grapples with her own identity and the responsibilities that come with her newfound powers. She joins the Order of the Cruciform Sword, a secret society of warrior nuns dedicated to battling evil forces. The series combines elements of action, mysticism, and drama as Ava learns to navigate her new life while uncovering secrets about her past and the true nature of her destiny.