Orphaned Mary Clancy (Hayley Mills) is sent by her wealthy Uncle George (Kent Smith) to St. Francis Academy, a Catholic girls boarding school and convent. He has sent her there to straighten her out as she is rebellious (amongst other things, she is a heavy smoker), and is always carrying out her dubious but "scathingly brilliant ideas". At St. Francis, she meets fellow student Rachel Devery (June Harding), recently transferred from New Trends Progressive School. Rachel is a follower, Mary her leader. The two continually lead other students astray, especially Mary's cousin, her Uncle George's daughter, Marvel-Ann (Barbara Hunter). They also butt heads with the school's equally strong willed Mother Superior (Rosalind Russell). Mary and Rachel's antics bring them close to the verge of expulsion, but the Mother Superior feels she needs to be part of Mary's salvation as Mary's primary alternative, living with her womanizing Uncle George is not even an option in the Mother Superior's view. Ultimately, Mary's inner curiosity and keen observances of life around her, supported unwittingly by the Mother Superior and the other Sisters, bring her to a turning point in her view of life at St. Francis, one at odds with her best friend.—Huggo