In the summer of 1937 World War II is only a distant cloud on the horizon. As the various Cazalet households prepare for their summer pilgrimage to the family estate in Sussex, we meet the entire cast. There's bluff, hearty Edward, in love with but by no means faithful to his wife, Villy; Hugh, wounded in the Great War, but devoted to pregnant Sybil; Rupert, who worships the body if not the mind of his child-bride, Zoe; and Rachel, the spinster sister, conducting a desperate clandestine love affair under the family roof.