When Ella, Brigit, and Jason return for their third year at the Arcanum Training Institute, they discover a dark plot brewing. Secrets and deception surround the magic school's founders, and the trio will stop at nothing to find out what really happened to the Institute's enigmatic Conjure architect. As they dive deeper into the mystery, it leads them to the Underworld and the Cards of Deadly Fate - a seemingly impenetrable prison full of villains. And worst of all, their old nemesis, Gia Trivelino, awaits them, ready to wreak more havoc. With tensions between Conjure folks and Marvellers at a fever pitch, the trio must face the living and the dead to get the answers they need to protect their world.