Jane Austen's "Persuasion" was published in 1817, after her death. The story follows Anne Elliot, who, at 27 years old, is considered a bit of a "spinster." Seven years earlier, she fell in love with Frederick Wentworth and was briefly engaged to him, before becoming convinced that he was unsuitable due to his lower class.
When the story picks up, Wentworth is back in town, now Captain Wentworth, having made a name for himself in the navy. Anne still pines for him, but he won't give her the time of day. Torn between her family and the love she let slip through her fingers, Anne must choose what to do.
It's unclear yet what changes the movie will make to the source material's plot.