"Broken Promise" is a cinematic reconstruction of the atypical wartime story of Martin Friedmann - Petrasek, a Jew from the small Slovak town of Bánovce. One of family of nice and the fifth son of poultry buyer, Martin was a talented soccer player, scouted by nationally-ranked teams in the idyllic pre-war era when the town of Bánovce was an ethnic and religious melting pot. For fun, he'd run to ring the bell of the local Catholic church with his soccer teammates.
The family's life began to change around the time of Martin's bar mitzvah, which was last occasion the Friedmann family celebrated together - the newly-formed Slovak state had just become an ally of Hitler's Germany and Mr. Friedmann makes his family promise that would all reunite here again in a year's time. It's a promise that could not be kept. Soon Mrs. Friedmann is seewing the yellow Stars of David on eight coats - only brother Alex has it sown on a yellow jacket, so that can keep on going to the movies - and Martin is expelled from the town's soccer team, much to the coach's chagrin. Jewish store are "Aryanized", yet when the Friedmanns have a chance to emigrate to Palestine, Mr. Friedmann refuses to take a chance on an overloaded ship and an uncertain future in desert: "What's the very worst thing that can happen to us here? That they make us work? The Germans are all in the army and they need other people to work for them! And so what, I'm not afraid of working..." It's a decision he quickly comes to regret - the transports East have begun starting and Martin's brother Alex and sister Rachel have to board a freight train to Poland. Martin, struck by the helplessness of his parents, decides to take control of his own life by joining an old soccer buddy of his, one Fred Mahler, in the Sered Camp for Jews. (Fred had been sending letters from there: he's looking for good players for lager team an assures Martin that he'd be safe there.)
Getting off the train in Sered, Martin is immediately robbed of his watch by a Slovak lager guard and quickly realizes that he'd made a mistake. He is trapped, however, and put to work in the carpentry shop. Slowly starving to death, he is forced to play in the brutal soccer games against the guards. He learns about Auschwitz before the 1942 deportation that is supposed to clear the camp, but ends up standing before a castle car with a number around his neck anyway. In the end, he's rescued by a German soccer fan that just happens to run the camp. His friend Fred Mahler, however, is not so lucky.
Having survived the last selection for Auschwitz, Martin gets on the mulberry-leaf-picking detail in Sered, which enables him to make a quick dash back to Bánovce one day. He finds only a sealed house - everyone has been taken away as well. But then one his older brothers, Vilo, who had been drafted into the Slovak army, shows up in the Sered Camp, though Martin never even tells him of what he'd seen in Bánovce.
Overworked and undernourished, Martin comes down with a double pneumonia and Vilo comes to the lager hospital to say good-bye to him: "Go in peace, brother, this is our fate," he tells Martin, but the doctor decides to operate on the soccer player. He drains the water from his lungs through an incision in his back, performed without any painkillers. Miraculously, Martin recovers - his escape from the grim reaper makes for such an inspiring story that the director of the camp sends him to a sanatorium to recover.
Martin ends up among tuberculosis patients in the High Tatra Mountains, hiding his Jewish identity, stuffing himself to the gills and fending off amorous advances, fearing potential exposure due to his circumcision. However, one day the medical staff determines that he really isn't a tuberculosis patient, and Martin is forced to take his fate in his own hands again.
He ends up working as subsistence laborer in a monastery and ultimately, under the new name of Martin Petrasek, as a "partisan" during the Slovak Uprising. He survives the last winter of the war in the mountains with a band of Soviet-led guerillas that are even bigger anti-Semites than the Germans. In a memorable scene, the Soviet soldiers have their healthy front teeth pulled out, that they could replace them with golden dentistry that would guarantee them upward mobility in the Soviet Union of iron teeth.
At the end of the war, Martin is reunited with Vilo. He also returns to Bánovce, but another family has been living in their house for the past four years and he has a hard time even convincing them to let him rummage around the family's old attic. But when he does, he finds a box with family pictures and an old yellow star - it's time to move on to Israel.