When the Cazalets' beloved matriarch passes away, she takes with her the last of a world in which they have thrived. Louise, now divorced, becomes entangled in a painful affair; while Polly and Clary must balance marriage and motherhood with their own ideas and ambitions. Hugh and Edward, now in their sixties, are ill-equipped for the modern world; while Villy must learn to live independently. But it is Rachel, who has always lived for others, who faces her greatest challenges yet... Events converge at Christmas and only one thing is certain: nothing will ever be the same again.