When three schoolgirls and a teacher from Appleyard College disappear on Valentine's Day in 1900, the event has a far-reaching impact on the rest of the school, as well as the nearby township. People quickly come up with theories about the disappearances as paranoia sets in and long-held secrets surface. As authorities get further into their investigation, the mystery surrounding the case seemingly deepens. Natalie Dormer ("Game of Thrones") stars in this adaptation of Joan Lindsay's novel of the same name.