Twenty-seven year old Englishman Bob Adkin meets twenty-five year old Ruth Eagel near the British Embassy in Berlin in 1935, just as Ruth is being confronted by several Nazi blackshirts. They are both journalists, trying to inform their home countries about the violent changes sweeping across Europe. Two years later, they meet again in the thick of the Spanish Civil War. In a period of leave in Barcelona, they marry, and by the time they escape into southern France with the help of Republican soldiers, Ruth is pregnant.
In a derelict French farmhouse, their daughter Susannah is born, at the same time as the son of a wounded Spanish woman, another refugee from the Civil War, is born just before she dies of her injuries. The Adkins adopt the Spanish boy alongside their daughter, and name the day ‘Gemini Day’.