THE TROUBLE WITH ANGELS

In 1960s Pennsylvania, a group of girls meet on board a train that is heading for a convent school. One of the girls, Mary, convinces the others to go along with a prank. Upon arrival, Reverend Mother is not amused and scolds Mary and another one of the girls, Rachel.

In an effort to make money, Mary and Rachel sneak fellow students into the cloisters for a tour. Reverend Mother punishes them with dish duty. Throughout the fall, the girls struggle with gym class, faking illnesses to avoid swimming. Frustrated, Rachel writes a letter to Mr. Petrie, the principal of her former school, New Trends, complaining about St. Francis, leading her to get punished with dish duty. Inspired by the soap, Mary conceives of a new prank, adding bubble powder to the sugar bowls in the sisters' dining room. Reverend Mother sends Mary to chapel as punishment. While there Mary shares a moment with one of the other nuns, Sister Ligouri.

After art class Mary wants to experiment with cement casting, recruiting her cousin Marvel-Ann as a model. It goes terribly wrong and the nuns work for hours to free her from the casting. Mary and Rachel are put on dish duty one more time before break.

Later Mary and Rachel run into Reverend Mother while out for a walk. When Mary imitates Sister Ursula's accent, Reverend Mother tells the girls that Sister Ursula worked to hide Jewish children during the war and was captured. Mary is conflicted after hearing the story, and her feelings intensify when she looks out the window and notices Reverend Mother putting out food for the birds. Before Christmas, the girls are forced to volunteer their time at a retirement home holiday party. Mary struggles seeing the challenges the residents face as they grow old.

Bored during "Silent Sunday", Mary and Rachel sneak into the basement to smoke. The smoke wafts out the window and frightens Sister Prudence, who calls the fire department and sends the whole student body into a panic. Reverend Mother considers expelling the girls, but after meeting with Mary's distant guardian, her Uncle George, she gives them another chance.

Next semester, Mary and Rachel join the band. When they sneak away from a class trip to spy on the New Trends band, Reverend Mother does not punish them as she can see their intentions are good, and they win the band competition.

When Marvel-Ann comes down with the mumps, Mary stays at school over Christmas break. She watches the sisters at Midnight Mass from the wings of the chapel and becomes inspired to join in worship. When Rachel returns from break, she struggles to finish her sewing class project and falls asleep in the classroom. As Reverend Mother finishes the dress, Mary sits with her and learns about her life and journey to the convent.

At their final swim class the girls are forced to confront the fact that they have missed out on years of lessons, and they are sent to clean the attic as punishment for lying about their illnesses. While cleaning they discover a goodbye gift for Sister Constance. Mary asks her about it, shocked that she would give up her vocation. Sister Constance explains that she will remain a nun, but is moving to a leper colony in the Philippines to teach sick children. Later Mary cannot sleep, but struggles to tell Rachel what is on her mind.

The girls are shocked to wake up and find out that Sister Ligiouri had died in her sleep. Reverend Mother remains stoic and Rachel accuses her of being cold, but Mary sneaks into the chapel to watch Reverend Mother's emotional goodbye.

On graduation day, Reverend Mother announces the names of the girls who are remaining at the convent to begin their novitiate, which includes Mary. Rachel is shocked at first, believing that Mary was brainwashed. With some nudging from Reverend Mother, the girls unite for a heartfelt goodbye, and Rachel accepts Mary's choice. Mary jokes that maybe Rachel will come back and join her, and Reverend Mother states “If she does, I quit.”