First in a Scholastic multi-platform series with some truly great authors writing individual books. This one introduces the characters and is slow to start but becomes more action packed as the four young people who have summoned the spirits of the Fallen (spirits who disappeared in the last great battle. Ticks all the boxes: gender, racial diversity, etc. Australia gets a guersney as Stetriol, the land where one of the "bad" spirits is incarcerated.