A violent love affair erupts between Suryn and Mother Joan to which neither wants, is able or in a position to admit. Indeed, Father Suryn calls it a possession. A tsadik whom he asks for help tells him that love is at the bottom of everything. In a bid to free the nuns from the daemons, Suryn gives them his soul - he kills two farm hands, thus condemning himself to eternal damnation.
The film is a Jerzy Kawalerowicz's adaptation of Iwaszkiewicz's short story of the same title, delving into the European them of the 'devils of Loudun'. Set in the Polish provinces, it strays from the social and political aspects of the romance between a priest and a nun and instead looks at the human, existential aspects set against the ideological boundaries of society and the authorities. The director talked about his perspective on the story in an interview with Ray Privette of Kinoeye,
Matka Joanna od aniołów is a film against dogma. That is the universal message of the film. It is a love story about a man and a woman who wear church clothes, and whose religion does not allow them to love each other. They often talk about and teach about love—how to love God, how to love each other—and yet they cannot have the love of a man and a woman because of their religion. This dogma is itself inhuman. The devils that possess these characters are the external manifestations of their repressed love. The devils are like sins, opposite to their human nature. It is like the devils give the man and woman an excuse for their human love. Because of that excuse, they are able to love.
Critic Konrad Eberhardt wrote about the director's style in the Film weekly in 1996, "The moonscape of Mother Joan of the Angels, the austere convent architecture, the white walls obsessively enclosing the characters (...) create a vision of a world made up of a huge number of road signs which have to be deciphered".