曼哈顿少女黛西（西尔莎·罗南 Saoirse Ronan 饰）来到乡下，住在婶婶佩恩（安娜·钱斯勒 Anna Chancellor 饰）的家中。在这里，黛西结识了艾德蒙德（乔治·麦凯 George MacKay 饰）和艾萨克（汤姆·赫兰德 Tom Holland 饰）等人，一群年轻人一起度过了一段宁静的日子。 　　然而，某一日，战争毫无预兆的忽然爆发，伦敦遭到了敌人的轰炸和占领，一片疮痍景象，黛西就这样失去了故乡。婶婶离开了农场，留下黛西等人，电力的中断导致一切都陷入了黑暗和停顿之中，黛西必须使用智慧和勇气保护这一片仅存的家园。在此过程中，朝夕相处使得黛西和男孩们之间产生了别样的情谊，在这片似乎被整个世界抛弃的小小伊甸园中，希望和绝望的故事轮番上演。American teenager Elizabeth "Daisy" is sent by her estranged father away from New York to the countryside of England to stay with her Aunt Penn. Her distant cousin Isaac welcomes her at the airport and drives her home. She is introduced to her cousins, seventeen year-old Eddie and young Piper and to their friend Joe. However Daisy is a resentful, needy of love and aloof girl who believes that she is cursed and that bad things happen wherever she goes since her mother died in her delivery. Aunt Penn is a busy woman who is studying the war scenario in England, which is on alert due to an imminent terrorist attack, and needs to fly to Geneva. However, the next morning, a nuclear bomb explodes in London and the authorities of the United Kingdom declare a state of siege. Meanwhile Daisy and Eddie fall in love with each other, but they are separated by the military, which sends girls to one camp and men to another. Daisy and Eddie promise to meet each other again. In a country at war, Daisy and Piper flee their lodging and cross England under martial law, trying to find Eddie and Isaac.