A lost grimoire. A dangerous new enemy. And a powerful magical weapon that could destroy the world. Jayne Thorne, CIA Librarian, is back for another exciting mission. When her mentor goes missing, Jayne is sent to Paris to find him, only to land in the crosshairs of a deadly terrorist organization and their diabolical weapon, a mysterious poison that renders their enemies powerless. Fighting to combat this weakness, Jayne struggles to make peace with her sister, who has been hiding the truth of their family history for years, and overcome difficulties with her shifter boyfriend, who can't quite sync up with Jayne's new powers. Even worse, the terrorists demand she locate a necromantic grimoire in France, or they will kill her mentor. As Jayne hunts for the grimoire, she unlocks the secret to summoning the Master of Shadows-a long-dead master magician possessing a dark and destructive magic. With this lethal power unleashed, she must protect her team from the worst magical threats they've ever faced...or suffer the deadly consequences.