The Academy of the Air trains the horses and their bondmates. A rigorous program ensures the best serve the Duke. Others become couriers or serve in remote outposts. The changes associated with pregnancy cause problems for the girl and the horse. When a bondmate becomes pregnant, she is dismissed and her horse destroyed. The winged horses cannot survive long separation from or the death of a bondmate.

The villain of the piece, the Duke's eldest son, William, wants only one thing in life, to bond with a winged horse. Determined to change the bonding process, he sacrifices his gender to pursue his goal. The pregnant mare Lark found was one of his, and he wants her colt to breed or to bond with him. Both Lark and Black Seraph, the colt, reject William.

Furious, after various efforts to gain the colt fail, William and his henchman suborn a disgruntled horsemistress and force her to help them steal the colt. The theft sets in train a series of events with significant consequences for Lark, Black Seraph, the Academy, and the Duchy.

Lark also finds that some perceived as enemies are friends. She eventually discovers a good friend in Hester Beeth, daughter of a high noble family. Others also gradually come to recognize Lark's abilities, but some persist in name-calling and put-downs, both among students and at least one horsemistress.

The new novel provides a role model for girls similar to the one Harry Potter offers boys. Winged horses and a plucky heroine should attract many readers. Like the Harry Potter novels, this novel and others planned will follow Lark through her years at the Academy of the Air. Toby Bishop is a new pseudonym for young adult author Louise Marley. At least two more books are planned for the Horsemistress Saga: Airs and Graces and Airs of Night and Sea.