The youngsters Susanne and Dan always want to know more. They've discovered ancient flint flakes and paw prints at the old quarry on their farm in Kentucky. And a car that can fly on its own! Now the curious brother and sister investigate pictures drawn by their great grandfather, Papa Dovey. He had drawn a map. But why did he give it to them? It takes encyclopedias and posters, songs and poems to solve this last puzzle. And the map looks like the moon! Where has Papa Dovey gone?