This is book number 4 in the Nathaniel Fludd, Beastologist series.
Is there no rest for the travel worn and weary? Not if you are Nathaniel Fludd, world’s youngest beastologist-in-training. All Nate really wants is to track down his missing parents, but when a unicorn falls mysteriously ill, Nate’s Aunt Phil makes it clear where beastologists’ duties lie: with the beasts who need them.
If ministering to the creatures of the world isn’t difficult enough, Nate and Aunt Phil must also keep them safe from a villainous man. Will Nate ever find the parents he is so absolutely convinced are alive?