In Second World War Poland, the Balicki family are living under Nazi occupation after the German invasion. Someone informs the Nazis that Joseph Balicki, a school teacher, has turned Adolf Hitler's picture to the wall; for this infraction he is arrested and sent to Zakyna, a brutal work camp in the mountains of Southern Poland. Anxious to escape, he becomes sick and it is eighteen months before he is well enough to pit this plan into action. He manages to hit a guard with a small stone shot from a catapult, knocking him out and giving Joseph time to take his uniform and wear it to leave with the other guards. He hides in a cable car and is discovered by a Polish peasant, who along with his wife hides Joseph for a couple of weeks at great danger to themselves. Joseph walks for a month until he reaches Warsaw but finds his family gone and his home burned out. His old neighbor tells him that his wife was taken away by the Nazis and his children are most likely dead. He is picking over the rubble of his home when he spots a letter opener his wife had given him in the shape of a silver sword. He turns to see a boy watching him and he wants Joseph to give him the sword. Joseph does on condition that Jan tells his children, should he run into them, that he is making for their grandparents' home in Switzerland and that they should meet him there. Jan agrees, and also returns the next day to help Joseph jump a train without being spotted.
After Joseph was arrested his wife was taken by the Germans. Now their three children, Ruth, Edek and Bronia, live in the cellar of a house that was burned down by the German army. Food is sparse but Edek is a gifted smuggler and brings what they need. Ruth starts a school in the cellar wand when she talks about it at the soup kitchen she is given school supplies and a Bible. In the summer they leave the city for the woods and Edek constructs a house with branches. Food is plentiful because the peasants are kind. Edek becomes one of the chief smugglers but is calling at a house in a neighboring village when the secret police were searching for hidden stores. They find cheese sewn into the lining of his cost and take him away. For two years there is no news of him; in August of 1944 the sisters realize things are changing. The Russians were coming to liberate Warsaw but the Poles end up taking the city back themselves. Running short of munitions,General Bor radioes the Americans and British for help. By January 1945 Warsaw is in Russian hands and the Nazis have gone. Ruth and Bronia are shocked when they return to Warsaw as it is decimated. They find the cellar they lived in before and set up home and Ruth starts her school up again.
They find a scrawny boy outside passed out from hunger and bring him inside. When he wakes he tells them his name is Jan but he is not very friendly. Too illl to leave, he decides to stay once he is well again. Ruth visits the Russian control post and asks for food and clothes, paper and pencils, and for their help in finding Edek. The sentry, Ivan, is kind and brings them as many supplies as he can. Jan scuffles with him and Jan's wooden box of treasures breaks to reveal the silver sword. Ruth sees it and begins to cry. Jan tells her of meeting her father and Ruth decides they must leave Warsaw for Switzerland.
They leave in the spring and head to Posen searching for Edek. They find that he has been sent to a camp for children with tuberculosis; however when they reach it they learn he ran away. They press on to Kolina for food and when Bronia is lost in a s Dudley at the soup kitchen she realizes a hand is holding hers and sees it is Edek. Reunited, they travel by train with hundreds of other refugees going to Berlin. After nine days they arrive and find a city in shambles. They are directed to a transit camp which is safe but over-crowded. They hear a chimpanzee has escaped from Berlin Zoo and bitten a policeman. Jan disappears into the city androids the ape. Bistro, the chimp, is immediately respectful to him and Jan leads him down the street to the zoo keepers.
The family take the Potsdam Road and jump on a cart that takes them into the American zone. Despite pleasant summer weather, Edek is no better. However he is determined to find out where Jan is stealing food so follows him but his poor health makes him slow and he manages to get both of them caught. Captain Greenwood is investigating what happenned when Ruth, Bronia and Jan appear in the courtroom. Ruth tells him Jan is the thief and Captain Greenwood gives him seven days' detention.
The children hide in a barn for shelter but are discovered by the owner, Kurt Wolff. After an initial altercation he invites them into his house where they stay as part of the family, Jan forms a special bond with their dog, Ludwig, who used to belong to their son who was killed on action. They hide whenever the Burgomaster comes around as he will send them back to Poland. They tell the Wolffs about the silver sword and it is given pride of place on the mantelpiece. The next day Edek hears a jeep in trouble and goes to help the driver. His kindness unfortunately backfires as the driver is the Burgomaster who pays the Wolffs a visit and tells them that the children have to return to Poland on the transport leaving at noon the following day. His pleas for the children falling on deaf ears, Kurt Wolff devises a plan for their escape. He finds two canoes that belonged to his son and puts them together so that the children can use them to make their getaway. In the early hours of the morning, Ruth and Bronia set out in one canoe, the boys in the other, with an additional passenger, Ludwig, who is devoted to Jan. Theu float downstream with the current but the moon makes them visible from the banks of the river. A soldier clambers into the water to try to stop them and even tugs a paddle away, and their are shots fired from the bridge. They continue down river but have to get out and push when they run aground. They float over the water, ride the rapids and find more still waters again until they get to the mouth of the Danube. They walk into the town of Falkenburg then get a lorry lift to Switzerland. Jan realizes in horror he has left the sword on the Wollfs mantelpiece and wants to go back for it. They wake to find him gone so Ruth sets her attention to getting her brother and sister and herself further into Switzerland.Edek can walk no further and collapses but luckily an American soldier drives by and picks them up. He turns our to have picked up Jan as well having found him asleep in the back of the truck. Joe, the American, drives them to a refugee camp and persuades them to take the children in but the camp superintendent refuses to allow them to cross the border into Switzerland without proof of identity or family vouching for them.Rith writes to the Wolffs for the sword to be sent, thinking this might help prove their identity. One day late in the month she is called into the superintendents office and he asks her to describe the sword in detail. She does, even mentioning the little piece on the hilt that is bent. He unrolls a parcel on his desk and shows her the sword, along with two letters, one from Herr Wolff and one from her father. Herr Wolff had pieced their family history together and sent it in the letter to the camp. Joseph Balicki is living on Appenzell on the other side of the lake. He will collect the children by boat and promises to telephone Ruth. However the line was bad and they couldn't talk in much detail. The Swiss boat due to take them over the water wasn't due for hours and they decided to take a walk. The air was heavy but they did not notice. In one huge downpour the lake grew choppy and they could not see where they were. They tried to go back for Edek whom they had left resting on a rock. Ruth clung on to the little rowing boat and she and Jan began to row.
When she opened her eyes it was dark and she was lying in a bunk. She heard her farher's voice and within seconds is in his arms. He shows her her siblings in neighboring bunks but has left the surprise until last - he has found their mother. Ruth has a happiness she cannot describe. Her mother has clearly suffered greatly as a prisoner in Germany but is filled with joy. Jan tells her he lost his treasure box bit shows her the silver sword tied tightly on a string around his neck.
The family start a new life in Appenzell, building a village for children orphaned by the war. Jan is adopted by the Balickis although he is still wild and only Ruth can really handle him. Bronia was least affected by the war and flourishes but Ruth becomes clingy and follows her mother everywhere. Eventually though she becomes confident again and how to university in Zurich, qualifying as a teacher and marrying a Frenchman working in the children's village. They set up home in the house opposite her parents.
Margrit Bakicki keeps her most treasured possession, the silver sword, in a velvet-lined drawer in her jewel box.