As Aileen, Maureen and Oonagh - the three privileged Guinness sisters, darlings of society in Dublin and London - settle into becoming wives and mothers, they quickly discover that their gilded upbringing could not have prepared them for the realities of married life. For the eldest, Aileen, in Luttrellstown Castle outside Dublin, being married offers far less than she had expected; for outspoken Maureen, in the crumbling Clandeboye in Northern Ireland, marriage means intense passion, but fierce rows; while Oonagh's dream of romantic love in London is shattered by her husband's lies. And as 1930s Britain becomes increasingly politically polarised, the sisters' close friends, the Mitfords, find themselves under the media glare - causing the Guinness women to examine their own lives.