Valdo, an ambitious young apprentice working for Leonardo Da Vinci's disciple, Francesco, is least happy when the scholar suddenly dismisses him. However, shortly afterwards, he receives a letter from a mysterious patron, asking him to locate one of the great master's missing codices.
To gain access to Da Vinci's last residence, the Manoir du Cloux near Ambroise, Valdo tells its new inhabitant, a courtesan by the name of Babou de la Bourdaisière, that he is Francesco Melzi's apprentice and that he wishes to examine the inventions that still remain on the estate.
Under this cover, he starts to scour the estate: Babou's bedroom, Leonardo's workshop, the grounds, and dovecot, leaving no stone unturned. In the course of his investigations, he encounters a wide array of intriguing characters: Saturnin, a suspicious looking guardian, as well as the King of France himself.
To complete his mission, he has to solve a series of enigmas set by the great master himself.