Barbara Vining (Glynis Johns) is seventeen-years-old and living with her family in a 1950s English town. Her father, Henry (Walter Fitzgerald), is a newspaper journalist and mother, Vi (Megs Jenkins), a homemaker; her maiden aunt, Evelyn (Pamela Brown) also lives in their home. Barbara attends a co-educational school. And, for the first time in her life, Barbara is in love. The object of her affection is a sensitive and handsome gentleman, Stephen Barlow (Leo Genn), who teaches Latin to the graduating class at her school. Barlow is an Englishman, married to a beautiful, but very insecure and lonely American lady, Kay (Gene Tierney). Barbara disappears after a tutoring session at the Barlow home and is "in absentia" for three days. During that time, Stephen Barlow is asked to resign and nearly cautioned by the police, as rumors have run amok throughout the town. Many people, including his wife, are uncertain regarding what to think. Was it simply a case of unrequited love or did Stephen Barlow have a torrid affair with young Barbara? Is she dead by her own hand, is she murdered or has she simply disappeared? When three days elapse, Barbara appears and many questions are answered. But, in the tradition of British film, many more questions remain.