Oh, what horrors we commit, large and small, from the moment we allow ourselves to decide that we are good and others are evil. Religious fanaticism knows no boundaries, nor is any religion exempt; those who believe have a great deal to answer for. "The Magdalene Sisters," a first feature written and directed by the actor Peter Mullan, is the story of a small horror, created by the Irish Catholic Church and supported by the willful ignorance and blind fanaticism of its believers, who worship the supposed purity of women in the image of the Virgin Mary; and who punish any woman who is, or even appears to be sexual. It is the story of the Magdalene Sisters' laundries, which operated throughout Ireland until just a few years ago, with the last one closed as recently as 1996.

The laundries, run by the order named for the woman who fell from grace but was redeemed by Christ's forgiveness, were repositories for women deemed to have fallen, like Mary Magdalene; they were expected to spend their lives like penitents. They were women - and girls - who had had sex before marriage, who were raped and therefore were now unclean, or who had even shown merely an interest in boys or men. They were taken, by their families or by the Church, to the laundries to live out their lives expiating their sins.

"The Magdalene Sisters" follows three young women: one who had a baby out of wedlock, one who was raped by her cousin at a wedding, and one, in an orphanage, who dared to talk to the boys who hung around. They are taken to one of the laundries, a profit-making venture for the order, where they will spend the rest of their lives unless they either are taken back by their families or can find a way to escape. They are in a prison in which they must not talk, must work and pray, and cannot communicate with the outside world. The laundry is run by Sister Bridget (Geraldine McEwen), a sadistic and rapacious woman who rules with her voice and punishes with her quirt.

As a film, "The Magdalene Sisters" can be appreciated for its message and its illustration of the injustice; but it has the weaknesses of the fervent. We are already on the side of the women imprisoned here, but Mullan spends his time showing us their pain and humiliation, repeatedly pointing out the cruelty, again and again. He tells his story like a documentary, and I'm sure the reality was at least as bad as this; but then he wants us to respond to his people as though they were characters in a novel. He hasn't given them the depth or complexity, though, to let us do it. What we see, powerful as it is, is all we get.

Nevertheless, the film is packed with extraordinary moments and images. Another inmate, called Crispina (Eileen Walsh in an amazing performance), a slow-witted young woman whose baby was taken away, has been given a St. Christopher's medal which she holds to her mouth when her sister, who now raises the boy, comes with him once a year, on his birthday, to the gate a hundred yards away from the clothes-drying lines, so that Crispina can speak to him, as she thinks, by holding her medal up to her mouth and whispering to him. She does not even know his name.

The laundry sits, walled in, at the edge of a town. One of the protagonists (Anne-Marie Duff, who looks like a young Meryl Streep) is at the bottom of the garden and sees an open, unlocked door in the wall. She opens it to a green vista of fields and woods, and the shock of its wide and calm beauty overwhelms us as it does her. And then she closes the door again.