The story focuses on Father Joseph Suryn, newly arrived in a village dominated by a convent swept by demonic possession. The young priest has been sent to aid in a long-term exorcism project; the entire convent, led by the title nun, seems to be possessed. Suryn is unworldly and aloof, while in the village the possessions and exorcisms are the stuff of gossip as well as superstition. What gives Mother Joan its distinctive quality is the way both the possessions and the exorcisms are treated as an almost-normalized public spectacle. The villagers gather to watch the nuns march into church, the next-to-last in line spinning around compulsively, and subject themselves to attempted exorcism. The efforts of the priests only inspire the nuns to frenzy, with Mother Joan herself the most flamboyant performer. In some way the spectacle resembles a show trial, except that justice, or the will of God, never seems to prevail, while the suspects freely confess their guilt yet refuse to repent. One character suggests that Christians embrace the concept of demonic possession because it somehow confirms the existence of God, and that seems to be a key to understanding this film.
Along the way, Suryn gets a major crush on Mother Joan. He tries to deal with it by flogging himself, but to no avail. Trying to get to the bottom of the possession question, he consults a Jewish rabbi who harangues him about the angels who mated humans and spawned a race of giants and finally tells Suryn that the two of them are the same. Given that they're played by the same actor, Mieczyslaw Volt, the rabbi has a point, though that fact also raises the question of whether the meeting was real or only in Suryn's head. In any event, Suryn finally decides that the only thing he can do to save Joan, and in some way save himself, is to invite the devils inside her to take him over. In fact, this licenses him to let the demons already inside him rise to the surface, with dire consequences for some of the other villagers....
Lucyna Winnicka is possessed by the turbulent spirit of Mother Joan of the Angels.
Mother Joan is not one of the "history of cruelty" films I've seen from all over Europe from the 1960s. Kawalerowicz doesn't make a fetish of the ordeals to which Joan is subjected, and we never see anyone burnt at the prominently displayed stake. His attitude toward the people of 17th century Poland is generally compassionate. The common folk are folksy and bawdy and musical and superstitious, unafraid to peep through a window to watch Suryn and Joan in bed together. This movie isn't really about the overwhelming oppressive power of the state or the church, focusing instead on one man's breakdown and its several causes. Volt makes the breakdown convincing, while Lucyna Winnicka in the title role catches the unstable ambiguity of a character self-consciously committed to her role in the exorcism drama. She tells Suryn that she enjoys being possessed; is she acting possessed when she says that, or is she embracing the liberating power of performance? Whatever the answer, it's all too much for poor Suryn, and the two characters arguably illustrate a dangerous distinction between internalized private and dramatized public religion, the one corrupting the other.
On the nunsploitation spectrum Mother Joan falls closer to the high-end, high-toned stuff like Black Narcissus than to the wild, salacious fare that gives the subgenre its name. Nudity is at a minimum here and there's no hint of lesbianism. That may disappoint hardcore nunsploitation fans, but if you just like to see women in habits acting nutty, this film as plenty of that to offer. In the bargain, you'll also get a persuasive period piece with strong performances that are marred somewhat by the awful English subtitles on the Polstar DVD. Spelling and grammar errors abound, and some lines simply don't make sense as translated. Fortunately, the story still makes sense and you can still appreciate the overall effort. This is another film of surprisingly subversive potential from a Communist country, and an interesting one by any country's standard.