Ashbys are an English country-squire family living at their centuries-old family estate Latchetts, in the village of Clare, near the south coast of England. Beatrice Ashby (Aunt Bee) takes care of the estate and of the four children of her late brother Bill. Since Bill and his wife died, Bee has kept the estate going by turning the family stable into a profitable business, combining breeding, selling and training horses with riding lessons. When Bill's oldest son Simon turns twenty-one, he will inherit Latchetts and a large trust fund left by his mother. Simon had a twin brother, Patrick, but soon after their parents died, he disappeared, leaving what was taken as a suicide note. Brat Farrar is a young man recently returned to England from America. As an orphan boy he ended up in the western US, where he worked at ranches and stables for several years and became an expert horseman until a fall injured his leg and he was left with a limp. On a street in London, someone completely unknown to Brat greets him as "Simon". This stranger is Alec Loding, a second-rate actor who knows the Ashby family intimately. He comes up with a plan to use Brat's resemblance to Simon and Patrick to his benefit. Brat should impersonate the missing twin, Patrick and as the elder brother, claim the trust and the estate. Alec would coach Brat on background details for a share of the profit. Brat is reluctant but eventually agrees, especially when he hears about the horses.