Anybody who thinks there’s much difference between fundamentalist Islam, the Jim Jones cult,and mainstream Christianity needs to watch Philomena, Steven Frears’s short, devastating film about the Sean Ross Abbey south of Roscrea in County Tipperary, Ireland.

One scene in particular haunts me. A group of teenage girls who attend St Anne’s school, which doubles as a home for single mothers, are waiting impatiently to enter a room. When the nun, one of their teachers, finally opens the door, they squeal wildly and rush inside. But this isn’t a line to get tickets for a Justin Bieber concert. These little girls, these children, are waiting to see their own children. It’s not an indictment of teenage sex, but of patriarchy. Philomena, the titular heroine, who is 17 but looks younger, was not raped or seduced by an older man. On the contrary, she has nothing but pleasant memories of losing her virginity. Her lover was not only young and handsome. He knew exactly where her clitoris was. But birth control wasn’t widely available in Ireland in the 1950s, and Philomena never had a sex education class. So she winds up pregnant. She’s treated, not as a single mother, but as a criminal, incarcerated in St. Anne’s for the crime of sexual intercourse. But that’s not even the worst part. St. Anne’s is not just an authoritarian reform school. It’s a baby mill. Her son is taken from her without permission and sold on the open market to rich Americans.

The action of Philomena begins 50 years later. We meet Martin Sixsmith, a former BBC journalist, who, in the aftermath of having lost his job as a Labor Party press spokesman, is looking for a new career. He’s thinking about writing a book on Russia history — he was the BBC’s man in Moscow — but his heart’s not really in it. Sixsmith is an Oxford graduate, an ex-Catholic, with the emphasis on “ex,” as much a representative of the liberal, secular side of the United Kingdom as the nuns who run St. Anne’s school are of rural Ireland. After Philomena’s younger child Jane approaches him to ask him to write a story on the loss of her older brother, he, reluctantly, agrees. A “human interest story” is a big step down in prestige, but Sixsmith is a true journalist with a journalist’s natural curiosity. He’s also desperate to get his career back on track.

Philomena, now an elderly woman, a retired nurse, has been looking for her son for decades. Even though she has gone back to St. Anne’s, the nuns have been of no assistance, and, as Sixsmith immediately suspects, have been deliberately stonewalling her. While the Sean Ross Abbey may have gotten a new liberal coat of paint, a younger, subtler mother superior and a black office manager, underneath it’s the same rotten old Catholic Church, a harsh, puritanical matriarchy acting as the local enforcer for the vicious patriarchy in Rome. That Sixsmith can see this almost instantly and Philomena cannot demonstrates just what a tight hold the church still has on her mind. She knows the nuns stole her child. She suspects that they’re stonewalling her, but she’s also unwilling to see the worst in people, even Sister Hildegarde, who will reveal herself as the vile old woman she is at the film’s conclusion.

“Why do you think they managed to lose all the records that will help you find your son,” Sixsmith says when Philomena shows him the restrictive adoption papers she signed, “yet managed to keep the ones that prevent you from contacting him?”

As the movie proceeds, we learned why. The nuns burned all the records documenting how they were selling children on the open market to rich Americans. The action now shifts to the United States, to Washington DC, where Philomena has agreed to accompany Sixsmith. Their relationship deepens. Sixsmith is the upper-class cynic. Philomena is the elderly working class, Catholic innocent. There’s a running joke about Sixsmith’s expense account. For him, the flight to Washington is just another business trip. For Philomena, it’s the entrance to a world of affluent privilege she never imagined existed. But it’s by no means one sided. Sixsmith is curt and perfunctory with service people. Philomena is keenly sensitive to the minimum wage employees who staff the airlines, the restaurants, and the hotels. It seems odd to us that Philomena would have to stop to go to confession in rural Maryland. “Confession,” Sixsmith growls. “That church should be confessing to you.” But Sixsmith’s blistering cynicism also seems misplaced.

In the end, it takes both of them to unravel the mystery. I won’t go into any spoilers, but they find out what happened to Philomena’s son. Sixsmith’s journalistic sleuthing takes them halfway there, but it takes Philomena’s ability to earn people’s trust to take them the rest of the way. The final hour of Philomena is, if anything, more powerful than the introduction. Frears knows exactly how to dramatize a mother’s instinctive love for the son she never met. Nothing about what he became surprises her, if only because she instinctively learned all about him in the brief period she knew him in his childhood. The journey takes them both back to Sean Martin Abbey, where we learn that the nuns who allowed her to deliver a baby via a “breech birth” without anesthesia as “penance,” who emotionally brutalized her, who not only stole her child but stole him on the open market are worse than even all this would have led us to believe. Few films manage to capture the most extreme, most sadistic side of a patriarchal institution like Philomena. Sister Hildegarde doesn’t so much speak her lines. She vomits them out, as much of a demon as Linda Blair was in The Exorcist. But, overall, Philomena didn’t make me want to go Jacobin and tear down the Vatican. It reminded me of a poem by William Blake.

“I went to the Garden of Love,

And saw what I never had seen:

A Chapel was built in the midst,

Where I used to play on the green.

And the gates of this Chapel were shut,

And Thou shalt not. writ over the door;

So I turn’d to the Garden of Love,

That so many sweet flowers bore.

And I saw it was filled with graves,

And tomb-stones where flowers should be:

And Priests in black gowns, were walking their rounds,

And binding with briars, my joys & desires.”