A mother and her three Edwardian children move to a country house in Yorkshire after the mysterious disappearance of their father. The children become fascinated by a nearby train and their kindness helps them befriend an older gentleman who may be able to solve the mystery of their missing father.

1922. Six months after Matthew's tragic death, his loss is still felt throughout Downton Abbey. Mary struggles to face a new future with her fatherless child, and is encouraged by the family to pick up the pieces. Accepting a new role on the estate, the now-eligible Mary also finds herself the reluctant object of attention from a number of eager suitors. With the twenties in full swing and the tides of change sweeping through Downton, Rose's continued...