In a Sydney suburb, two nurses, Maria and Flora, a housekeeper, Lotte, and a solicitor, Arnold, attend to Elizabeth Hunter as her expatriate son Sir Basil, a famous but struggling actor in London, and daughter Dorothy, a divorced and down at heel princess, convene at her deathbed. They come to make sure they can leave Australia with their hefty inheritance.

In the early 1900s, Miranda attends a girls boarding school in Australia. One Valentine’s Day, the school’s typically strict headmistress treats the girls to a picnic field trip to an unusual but scenic volcanic formation called Hanging Rock. Despite rules against it, Miranda and several other girls venture off. It’s not until the end of the day that the faculty realizes the girls and one of the teachers have disappeared mysteriously.

In real life, mystery writer Agatha Christie disappeared for 11 days in December 1926. To this day, no one knows the details of what she did during that time. The film gives a fictional account of Christie’s time away, showing her as a woman fleeing her own life after the death of her mother and the announcement from her husband that he is leaving her. She flees to a spa in Harrogate. With the whole country looking for her, an American reporter finds her and ultimately tries to help her.