After nine days on the train, the Balicki children and Jan finally reach Berlin. Like Warsaw, the city has been largely destroyed by the bombing, but this does not bother the children, as they have grown used to such surroundings and feel good about their progress toward Switzerland. As they leave the train station, Jan, who is nonchalantly crossing the street, is nearly hit by a vehicle carrying a British officer. Eventually, the children find a place to stay at a transit camp in an old cinema, where groups of refugees are grouped according to their country of origin. One morning, a wave of panic runs through the crowded cinema. It turns out that a chimpanzee who escaped from the zoo was trying to get into the building. Jan is very excited until he hears that the chimpanzee has been chased away. They hear someone reading a newspaper article that describes how the chimpanzee, who is highly intelligent and friendly, escaped from the zoo. At the same moment, Ruth realizes that Jan has also disappeared.

It turns out that Jan has decided that he will find and rescue the chimpanzee, a plan which takes him several days to accomplish. The chimpanzee appears one day and jumps into a British Army vehicle—the same one, in fact, that had nearly hit Jan on the street. The chimpanzee is jumping up and down and scaring the people around him, in part because they are afraid that he will send the vehicle careening down the street. At that moment, Jan appears and calls the chimp by its name, Bistro, and offers it a cigarette, a habit the chimp picked up at the zoo. Jan gets Bistro under control, befriends him, and turns him over to the zoo keeper. The officer in charge of the vehicle invites Jan back to his lodgings for dinner. Jan shows up, along with the Balicki siblings, and the officer feeds them and provides them with supplies and food to help them as they continue their journey to Switzerland.

The children head south from Berlin. Their travels take them through the Russian zone of occupied Germany, where they see convoy after convoy of Russian soldiers and support staff. With the money Jan got as a reward for finding the chimp, and the supplies given to them by the British officer, the Balicki children and Jan are able to make their way south without too much trouble, especially as they are able to find a few rides in empty carts and trucks that are part of the military caravan. Eventually, the children cross into the American zone, which represents the last stage of their journey before they reach Switzerland.