When children encounter war it is not as the thing that Carl von Clausewitz called politics “by other means.” It is to their terrified eyes an impersonal force, one that takes away a parent or obliges one to hide, steals food from a plate or turns a school into rubble. War heightens the already helpless state of childhood. It removes the last vestiges of predictability and sense, offering randomness and brute violence instead — bombs that may crash through a ceiling at any moment.

The New York Times

The Ukrainian artists Romana Romanyshyn and Andriy Lesiv understand this. It’s why — though they’ve lived through a revolution in 2013, the Crimea annexation in 2014 and the ongoing conflict in eastern Ukraine — there is no explanation for the catastrophes that overtake a fictional town in their picture book, “How War Changed Rondo.” War is “War,” a monstrous dark cloud that sprouts fists, reducing everything it touches to “nothingness.” It is sudden in its appearance and unrelenting in its destructiveness, like anger itself.

Romanyshyn and Lesiv deploy a charming combination of drawing and collage, pasting in diagrams from botany textbooks and old newspapers. There is a fragility to the arrangement, which looks scattered on the page, and a fragility to their three main characters: Danko, made from a strand of light; Fabian, a fuchsia balloon dog; and Zirka, an origami bird. The trio love their idyllic town and its most famous feature: flowers that sing.

War obliterates all, seeding a thicket that blots out the sun. “Without light, the delicate and defenseless flowers of Rondo started to weaken and fade, sapped of the strength they needed to raise their faces to the sky. Saddest of all, they stopped singing.”

The book’s pages, shaded soft green and mustard yellow at first, turn the color of bruises, obsidian black and purplish gray. Danko, Fabian and Zirka dodge cutout bombs and tanks.

Light must then defeat the dark. It’s a fairly tired metaphor, but Romanyshyn and Lesiv grab onto it. How else to avoid the nothingness? The three friends, a little cracked and burned, rally the town to build a “light machine.” Metallic gears and screws roll onto the page. Soon yellow beams are puncturing the shadowy form of War, until “every black flower had disappeared and the darkness had dissolved completely. VICTORY!” Rondo returns, but its famous multicolored flowers have been replaced by red poppies.

A note informs us of a fact that might be common knowledge to a European child: The red poppy, since the onset of World War I, has come to commemorate those fallen in war. That this final visual punctuation mark needs explaining goes to what might make this book difficult for some children. It speaks so precisely to the perspective of a young person who has experienced the confusion of war that the indiscriminate brutality might feel abrupt and inexplicable to one who hasn’t. What is this dark force? Why has it arrived? Why has it landed on us?

If the book prompts these questions, maybe that’s OK. After all, Romanyshyn and Lesiv give their plucky characters a happy ending and more control over reality than a war would grant. The power of light over darkness and the return of singing flowers, illusory or comforting, are fantasies a terrorized boy or girl — or really any of us — surely needs to cling to.