Twelve-year-old Gerta’s family is divided by the overnight construction of the Berlin Wallshe, her mother, and her oldest brother, Fritz, are trapped on the East side, while her father, having gone in search of work with Gerta’s middle brother, are unable to return home from the West side. It isn’t until Gerta mysteriously receives a strange drawing that she realises her father wants Gerta and her brother to tunnel their way out of East Berlin. But if they are caught, the consequences will be far worse than grave. Stakes are as high as they possibly can be, but Gerta must find her way to freedom.