On May 10th, 1940, Nazi Germany attacked France, Belgium, the Netherlands, and Luxembourg. Their advance was swift, and led to the fall of France just six weeks later. In the fictional French village of Pontain-L'Écluse, 13-year-old François is shocked to see his fellow villagers—and even some of his family members—accept this occupation and submit to the laws and behavior of the German invaders. Determined to thwart the enemy, he enlists his friend Eusèbe to help sabotage the Nazis and motivate his village to unite against them. A fascinating tale of the Resistance and of actions taken by its youngest activitsts, inspired by true stories.

Thirteen-year-old François and his two best friends continue to thwart the German occupying forces in their small French village, secretly and successfully coordinating operations. But when their activities escalate and their small network gets involved in extracting prisoners of war to the Free Zone, to England, or their faraway countries of origin, the stakes are ratcheted up, and a deadly crackdown begins after one of their operations goes south.

More determined than ever to fight against their German occupier, 14-year-old François and his friends team up with a British spy who sends them on increasingly dangerous missions. Meanwhile, the war itself intensifies as the USSR and the U.S. join forces to fight the Nazis, and the children try to figure out what the various political parties are about, and what will be at stake when the war is over. In France, antisemitism continues to grow, and the Communist Party launches the first armed attack against the occupying forces.

For 14-year-old François and his fellow Resistance fighters, the situation in both their village and the country as a whole keeps deteriorating and the stakes keep rising: one of the townsfolk has begun denouncing Jews to the Nazis; the kids suffer another tragedy when someone close to them is killed in action; and the persecution of the Jews reaches previously unimaginable heights. In the face of such threats, the Resistance begins to bring itself together, uniting different movements and improving its radio communication, intelligence, and escape networks—largely thanks to members like François and his friends.

France has been under occupation by Nazi Germany for over two years now, and the French population is suffering under shortages, forced transfers to factories in Germany, constant propaganda, conflicting political views, and the brutal presence of a new pro-Nazi French militia. Nevertheless, hope remains alive as German troops are experiencing their first major defeats, and the Resistance network keeps growing. Communication with London is steadily improving too as radio operators risk their lives to transmit from inside the Occupied Zone. The children's new mission is to help these operators get their coded messages to the Allies... Easier said than done!

As François and his friends continue to carry out their usual Resistance activities, a threatening new law is announced: young Frenchmen would now be sent to work in the factories of Nazi Germany, whose own young men were now deployed in battle across the continent. This provides a new challenge for our young heroes, but also an opportunity to encourage the French to engage in civil disobedience and to recruit new members for the Resistance.