Indulge me while I practice summarizing the story. I'll reward you with a picture afterward.
The book is the journal of our protagonist, Hoshi, a fourteen-year-old girl whose mother hasn't been seen for ten years - until today, when Hoshi is waiting for her dad to pick her up from school, and a car pulls up with her mother in it. Only Hoshi soon finds this isn't her mom, but a shapeshifting tanuki - a trickster spirit - named Kichi, who claims to be her mom's friend. Hoshi's mother was kidnapped all those years ago, and now the kidnappers have taken her father, too. These aren't ransom-demanding criminals: they're the unpredictable kitsune, trickster fox spirits. When they struck ten years ago, taking Hoshi's mom as well as Kichi's tanuki beloved, the kitsune left no trace, but this time, they've made mistakes. Which means that Hoshi and Kichi - along with the secretive Alex, a boy with a mission of his own - are coming to the rescue. In a day, Hoshi goes from a regular teen to a girl who rides dragons (as a passenger on Tatsu Air), hides out at the bottom of Lake Michigan (as a guest of its little-known guardian, Mishipeshu), and searches the largest bookstore in America for the one book that could hold the key to beating the kitsune and putting her family back together. That's a lot to deal with, so Hoshi sorts things out by writing and drawing in her math-notebook-turned-journal.
Right! Picture time. Here's what the main characters look like in the style of Hoshi's illustrations.