1961年,柏林圍牆一夜升起。葛塔的世界,被硬生生劃成東與西。父親與哥哥滯留西柏林,她與母親、弟弟困在東柏林。士兵持槍巡邏,鄰居彼此猜疑——整座城市像一座監牢。直到某天上學途中,葛塔看見父親站在西邊瞭望台,用奇怪的動作比劃著訊號。她明白了:父親要她挖地道,逃出去。但只要被發現,代價就是死亡。在監視與背叛無所不在的年代,自由,必須用勇氣換取。With the rise of the Berlin Wall, twelve-year-old Gerta finds her family suddenly divided. She, her mother, and her brother Fritz live on the eastern side, controlled by the Soviets. Her father and middle brother, who had gone west in search of work, cannot return home. Gerta knows it is dangerous to watch the wall, to think forbidden thoughts of freedom, yet she can't help herself. She sees the East German soldiers with their guns trained on their own citizens; she, her family, her neighbors and friends are prisoners in their own city.But one day, while on her way to school, Gerta spots her father on a viewing platform on the western side, pantomiming a peculiar dance. Then, when she receives a mysterious drawing, Gerta puts two and two together and concludes that her father wants Gerta and Fritz to tunnel beneath th