This is a story about an ecosystem - based on a real event, apparently. By accident, a family of wolves leaves the small island where they live. As apex predators, their presence had been keeping the island ecosystem in balance, but without the wolf family, the deer population increases. They eat more food, and there's less for rabbits and mice, and less too for the owls that feed on these small herbivores. All the creatures on the island begin to starve, until the wolves are able to return to the island and ecological balance is restored.

It's attractively illustrated, but the real strength here is the science it conveys. Would be a great book for teaching kids about basic ecology and conservation science!