A young woman is brought back from the dead after coming into contact with an ancient artifact, leaving her wandering the streets of Spain with supernatural powers — unaware of the dangers that swirl around her.

The Order's search for Ava and their missing halo leads to the advanced technology firm ArqTech, where Ava and her new friends have crashed a party — unaware that a powerful demon is also searching for her, to turn the balance of power between good and evil.

Back in the custody of the Order, Ava learns of the destiny that the church believes she has been given by heaven. While Mother Superion begins Ava's training, the ArqTech head too learns of the young woman's unique abilities.

The Cardinal sends the nuns to infiltrate ArqTech to steal its divinium treasure. Elsewhere, Ava considers leaving town to find a fresh start, but is drawn back by unfinished business.

Ava boards a ship to escape with JC, but is pursued by both Sisters Mary and Lilith. Jillian Salvius goes public with a claim that her technology will create a bridge to Heaven, challenging the Vatican.

Ava reluctantly finds herself on the road with Mary, who takes her to an out-of-the-way village where they can recuperate — and give Ava a chance to reassess who she is and who she will be.

Ava approaches Jillian Salvius to allow her to study her powers and her halo. Meanwhile, after a group of rejected candidates arrive at the Order's home, the nuns are stunned to learn that several of their own are being transferred.

The Order discovers a dark secret held by the Vatican, and Ava begins training to infiltrate the capital of the Church to stop Cardinal Duretti from seizing a supernatural power. Lilith returns from beyond, and Beatrice confides in Ava.

Ava leads her team to infiltrate the Vatican, searching for an ancient relic they hope to destroy — while the Order's newest recruits target them. Lilith takes matters into her own hands.

As a new pope is named, Ava makes a shocking discovery inside Adriel's tomb. But an ancient tale of good and evil proves to be more complicated than it appears.