In 1929, John Whittaker (Ben Barnes) returns home to the family estate after a lengthy absence on the continent. His mother is thrilled at the news of his return, but is shocked when he arrives with his new bride, Larita (Jessica Biel). Not only is he married, but she is a blonde American who has a mind of her own and an interesting occupation: a race car driver who just won the race at Monte Carlo. John's father, Mr. Whittaker (Colin Firth), takes an immediate liking to her, but as far as his mother is concerned, she is the worse possible choice. She is also concerned that her son will soon leave again as Larita is expecting them to relocate to London after a short visit. Mother has her own ideas and soon it's outright war between them. When Mrs. Whittaker learns something about Larita's past however, it creates a rift between her and John that may be irreparable.