"The Marvellers deserves the highest compliment I can give a book: I want to live in this world." --Rick Riordan, #1 New York Times bestselling-author

Eager to wield their stapiers for Marvel Combat, Ella, Brigit, and Jason are back for their second year at the Arcanum Training Institute. With Ella's celebrity growing throughout the Marvellian world after thwarting the Ace of Anarchy's diabolical plans, it's proving hard for her to focus on her coursework. But back home in New Orleans the Conjure community isn't too happy about her return to the skies for another year learning to become a Marveller. As if life wasn't complicated enough, Ella soon discovers more dangerous secrets about the Conjure architect who built the school.

Before she can dig deeper, a mysterious magical illness sweeps through the Institute, and Ella lands at the top of the suspect list. Can Ella and her friends save themselves and the Marvellian world before chaos breaks loose?