Take one farm in wartime England, a motherless young girl and her father.  Add a young woman bombed out of her London office, a beautiful but selfish younger sister, a sick mother, a resentful housekeeper, a retired colonel and his daughter at the Big House, and a canny old codger too old for the army.  Mix well and leave to simmer for a delicious frothy summer confection.
Originally published in 1943.