'Gemini Day' is the rollercoaster epic of an Englishman and an American woman who meet and fall in love in the Spanish Civil War. They are both journalists forced to flee to southern France. In an old farmhouse, Ruth gives birth to their child, Susannah, on the same day as a fugitive Spanish woman shot by Nationalists gives birth to a son and dies almost immediately. Ruth and her husband Bob adopt the boy and call him Rafael after his murdered father. They name the day when their children were born as Gemini Day, and the story tracks the Gemini Days of the future.