London, 1962. Two teenage girls - GINGER & ROSA - are inseparable. They skip school together, talk about love, religion and politics and dream of lives bigger than their mothers' domesticity. But the growing threat of nuclear war casts a shadow over their lives. Ginger (Elle Fanning) is drawn to poetry and protest, while Rosa (Alice Englert) shows Ginger how to smoke cigarettes, kiss boys and pray. Both rebel against their mothers: Rosa's single mum, Anoushka (Jodhi May), and Ginger's frustrated painter mother, Natalie (Christina Hendricks). Meanwhile, Ginger's pacifist father, Roland (Alessandro Nivola) seems a romantic, bohemian figure to the girls. He encourages Ginger's ‘Ban-the-Bomb' activism, while Rosa starts to take a very different interest in him. As Ginger's parents fight and fall apart, Ginger finds emotional sanctuary with a gay couple, both named Mark (Timothy Spall and Oliver Platt), and their American friend, the poet Bella (Annette Bening). As the Cuban Missile Crisis escalates - and it seems the world itself may come to an end - the lifelong friendship of the two girls is shattered. Ginger clutches at one hope; if she can help save the world from extinction, perhaps she too will survive this moment of personal devastation.And then Rosa develops a crush on Ginger's father, Roland - a man of radical politics, driven by a lust for personal freedom. The crush becomes an obsession, the obsession becomes a flirtation and then - irrevocably - a secret affair. The girls' friendship is shattered. The secret affair becomes a ticking time-bomb within an already precarious family.
The crisis in the family and in Ginger's psyche - carrying the burden of secrecy,
contorted by feelings she can barely control - is echoed in the world around her as the Cold War nuclear race comes to a head with the Cuban missile crisis. A private war breaks out, with deadly inevitability, as Roland's lies and secrets unravel. Ginger starts to believe that if she can help save the planet from extinction, perhaps she too will live beyond this moment of private annihilation.