One evening, ten-year-old Louna discovers two strange visitors in her room—a little ghost girl and her mossy little dragon. They tell her they live at the bottom of a well in an abandoned garden where Louna often walks with her dog, the Fox. Ghosts? Little dragons? It could have seemed like a dream if, in reality, terrible events hadn’t begun: it seems the forest and the fog are moving closer to the city, and… pets are disappearing! The Fox is in danger, and Louna has no choice but to find out what’s happening here.