Miss Trafalgar and Dorothy Boone have grown comfortable in their partnership. The rough edges on the society they formed with their fellow adventurers have begun to smoothe, opening the doors for a new era of cooperation among one-time enemies.

When Trafalgar receives an Egyptian statue, a gift from her former assistant, she asks Dorothy to determine its authenticity. What Dorothy uncovers throws both of them, along with the rest of the Mnemosyne Society, into chaos. With lives at risk and the future at stake, Trafalgar leads a group of reluctant allies from London to Egypt to stop an unspeakable power from falling into the wrong hands.

Meanwhile, Beatrice Sek continues her quest to discover her true origins. Armed only with the knowledge that she is one of four "Elementals," she spends her spare time searching for anyone who may know where she came from. She receives unexpected assistance from a former foe, a powerful enemy who promises to help her find answers. The offer is too good to refuse, no matter who it's coming from, but Beatrice may soon find herself forced to choose between revelation and surrendering her soul.