‘I have saved three lives; give me three more. Here are three opals. Your children will be the other.’ Marseille, 1561. With these enigmatic words, a mysterious doctor bid farewell to the three shipwreck victims that he had taken in and saved from the plague. But what became of these three escapees? And what did they do with the opals they received from their savior?

Bordeaux, 1628. The young and beautiful Walaya du Martray is hearing the last wishes of her dying father. He begs her to honor the promise he made, as a child, to the doctor who saved him after a shipwreck… a man named Nostradamus. Above all, he wants her to recover the opal that was entrusted to him, and to find those that were given to the two sailors saved along with him. Joachim the alchemist, Erik the mercenary, and Walaya the adventurer: these three are the heirs of those men. The opal that each possesses will determine their destiny. Together, they form the Opal Conspiracy, which will seek to illuminate the mysteries left behind by Nostradamus seventy years earlier.

But the menacing guild known as ‘Ars Magna,’ whose members include the powerful Cardinal Richelieu, will do everything in its power to stop them… It’s got all the ingredients of a great adventure story: a thrilling mystery, vivid characters, towering historical figures, an era full of danger — and, to spice things up a bit, a healthy dose of the occult.