On Sunday morning, August 13, 1961, Gerta awoke to discover that a wall of barbed wire had been built through Berlin to separate East and West. Her father Aldous and brother Dominic were trapped on the other side in West Berlin, while Gerta, her devastated mother, and older brother Fritz were trapped in the East with no way to contact them.
The story flashes forward 4 years later where the wall has been built to twelve feet high and four feet wide, with guards all around. It is impossible to cross and those that try are often killed. Twelve year old Gerta desperately misses her father and brother. She secretly hates the wall that imprisons East Berlin and despises the constant fear and lack of freedom imposed on the citizens. She doesn't fully express this to anyone except her brother Fritz because the risk is too great. Even her best friend Anna encourages her to keep quiet and to just do what she is told in order to stay out of trouble. One day, when Gerta is furtively looking at the wall, she spies her brother Dominic and father on the other side! It is the first time she has seen them in four years! Her father appears to be sending her a message but before she can figure it out, Gerta is quickly and harshly reprimanded by a guard, Officer Muller, for even looking in the direction of the wall.
Eventually, Gerta uncovers the meaning of her father's message. A way to escape East Berlin is by digging a tunnel from the basement of a building that sits against the wall. It is a perilous plan that could result in getting killed by the Stasi, Secret Police, or the Grenzers, border guards. However, Gerta manages to convince Fritz to take the extreme risk and together they begin to dig the tunnel in secret. They are desperate to finish before Fritz is forced into the army where he is certain he will lose what little freedom he has forever. Gerta and Fritz are careful to hide their efforts by using the dirt from the tunnel to plant a garden in front of the building.
One day while digging, Gerta and Fritz discover that their father and brother have been tunneling from the other side! They convince their mother that it is time to escape and they bargain with the East German guard, Officer Muller, to join them with his family. While they make their dangerous escape, Gerta's best friend Anna also joins them with her family. The courageous group are almost through the tunnel when they are discovered by Grenzers. They race towards freedom with guards shooting at them!
Officer Muller pushes Gerta out of harm's way and sacrifices himself. He is tragically shot and killed by the Grenzers. His wife and child along with Anna and her family and Gerta and her family are able to make it to the other side of the tunnel to West Berlin and to freedom. They are all overjoyed. While it is true that the sun always rises in the east, on that day Gerta felt as though it truly rose in the west as it was the end of their long, dark night.