Delphine Lecompte has devoted her journalistic career to exposing secrets, but there's one mystery she's never been able to crack. After her mother's assassination when Delphine was eight, the police were unable to locate her father, or any record that he ever existed. An anonymous donor paid for Delphine to attend an elite boarding school. When she broke into the school office to find her records, Delphine discovered the tuition cheques were being sent from Paris. The address eventually led her to the Palais de l'Institut.

Inside the palace, five councils operate in utmost secrecy. The oldest council is L'Académie Française. Composed of forty members of the literary community who call themselves "Immortals", the Academy oversees the purity and correct usage of the French language - though their true purpose is far more sinister.

When a member of the Academy vanishes under mysterious circumstances, Delphine recognises his photograph as the newspaper comes off the press - it's her father, who she hasn't seen in nearly twenty years. Delphine reluctantly teams up with her ex-fiancé Laurent, a Flemish scholar who has his own urgent reasons for investigating the French Academy. And as they immerse themselves in a world of deadly secrets, they uncover a conspiracy going back centuries...