Set during World War II, Secrets of War follows two best friends, Tuur and Lambert, who find themselves caught up in the turmoil of the war. As the Nazi occupation intensifies, the boys must navigate the complex and dangerous world around them while trying to maintain their friendship and protect their own secrets.

The Duch painter Vincent Van Gogh grew up in the family of a stern Calvinist country pastor, feeling a misunderstood misfit, obsessed by painting, while his elder brother Theo left for Brussels, later Paris, and became an art dealer. Vincent tried an alternative career as missionary to the Catlolic Walloon mineworkers in the Ardennes but returns, broke and failed again. Later he'll move in with Theo in Paris, but can't fit in business or society. Vincent heads for frustration and health drama. His heir, a Dutch railway engineer, later visits those places while deciding whether to sell the family paintings collection to invest in the super-fast railroad.

Kiek is worried as her father works in a war zone. To lengthen the odds of her father getting hurt, she comes up with a strange and unique idea: she needs a dead dog and a dead mouse, because Kiek doesn't know one person who has a dead mouse, a dead dog and a dead father. Surely the odds against that are enormous?