He has been sent to investigate a case of demonic possession at the nearby convent after the local priest, Father Garniec, was burnt at the stake for sexually tempting the nuns.

After a failed meeting takes place between Father Suryn and the local rabbi, the priest re-enters the convent and receives Mother Joan's demons through his love for her.

At night, reasoning that the only way to save the abbess is by doing Satan's bidding, Father Suryn grabs an axe and kills Kaziuk and Juraj, another stableman.

This film is very loosely based on the real life outbreak of mass hysteria in the French town of Loudun in 1634 that occurred when a convent of Ursuline nuns, led by the hunchbacked Sister Jeanne of the Angels, became obsessed with a handsome, womanising priest, Urbain Grandier.

The nuns continued to be possessed for four years after his death, and further exorcisms were carried out by the sincere and deeply spiritual Father Joseph Suryn whose main concern was helping Sister Jeanne.