When Luna can't sleep, she discovers a strange creature in the moonlight outside her window, a kind of flying balloon fish that is neither fish nor bird?

She doesn't understand what it says, but Luna decides to find out where it really belongs. Maybe it can fit into the city if she dresses it up? Maybe it lives in the ocean with other fish?

But how is she supposed to know where it lives when she can't understand a word it says? It makes such strange sounds, maybe they can understand each other in ways other than words? What if they talk by drawing, by dancing, by singing? Will she understand the moonfish then?