On a crisp March morning in 1932, bride-to-be Dolly (Felicity Jones) is hiding in her bedroom daydreaming of the whimsical summer before, helped along by an ample jug of rum. Long-lost cousins and quirky aunts are arriving to the house every hour, and the downstairs living rooms are buzzing with speculation about the bride's whereabouts. Exasperated by her daughter's absence, Dolly's scatterbrained mother Hetty (Elizabeth McGovern), is at her wit's end, scurrying around the house trying to quell the relatives' suspicions. Hetty has perfected all of the day's arrangements, but her plans can't prepare everyone for the arrival of Dolly's unpredictable former lover, Joseph (Luke Treadaway).
In the lead up to World War I, fresh-faced graduate Friedrich Zeitz (Richard Madden) becomes the right hand man of the powerful but aging mining tycoon Karl Hoffmeister (Alan Rickman). As Hoffmeister's health begins to fail, Zeitz is brought to his vast country manor to maintain the business alongside him. Zeitz falls hopelessly for Hoffmeister's stunning young wife Charlotte (Rebecca Hall) knowing that his infatuation can never be realised. But just as they open their hearts to allow a chance of love to blossom between them Zeitz is sent to South America on business. When the Great War erupts Zeitz is stuck half a world away with no chance to return. Eight years later, with millions dead and Europe in ruins, the exile returns to his homeland and to the woman he hopes has been waiting for him.