The Trouble With Angels

Rebellious Mary Clancy (Hayley Mills) and follower Rachel Devery (June Harding) meet on a train on route to the St. Francis Academy, a Catholic boarding school for girls located in a drafty old castle. 

Mary comes up with loads of "scathingly brilliant ideas" that Rachel goes along with, such as giving tours of the nun's private quarters to the other girls, putting bubble bath powder in the nun's sugar bowls, smoking cigars in the basement, which inadvertently sets off the fire alarms, and sliding down the outdoor chute. Unfortunately, they always get caught.

As they return each year, slightly more grown up, Mary begins to respect what Mother Superior (Rosalind Russell) and the other nuns do, not only for their students but for the residents in the nearby town.   

Based on the novel by Jane Trahey.