Matt Cruse is a Cabin boy for an airship, called the Aurora. Matt spots an old man in the basket of a hot air balloon, Matt saves him and finds out the man had spotted a different kind of creature. While the Aurora was boarding one day he met a girl named Kate De Vries and he finds out she is the old mans Grandaughter. They both set off looking for them and they find the skeleton of a bird they call the cloud cats. While they try to bring the skeleton back to the ship they find pirates. Now they have two problems, trying to bring the skeleton to the ship, and they must save Matts home and everyone on the ship!