Gerda is ten years old, Otto is twelve. They are brother and sister. Gerda loves adventure and imagines herself as a musketeer. Otto is interested in geography and sits with a book all day. Like all children, they quarrel, make up, and play hide and seek. Unless they dine very modestly - after all, it’s war now. One day they meet other children, also brother and sister. Only these children are in danger, even death. Moreover, now both Gerda and Otto’s parents are in danger. Gerda understands that everyone needs to be saved.