In St. Mark's found fake coins, which, oddly enough, minted of pure gold King Joan instructs his friend Marc de Segur to sort out this complicated matter. Mark soon learns that traces of counterfeiters lead to the province of Poitou, where recently was killed the royal sheriff of Lacroix, who conducted a secret investigation into the activities of the local prevo .. But once Mark arrived in Poitiers, there were new murders, and near the crime scene saw a man in a black cape and an iron mask. Who mints fake coins from pure gold? Why was the royal sheriff killed? Are these crimes connected with the mysterious man in an iron mask and the recently destroyed Order of the Black Mirror? And who is hiding under this mask? To answer these questions, Mark will have to trace the path of Sheriff Lacroix. find a secret mine in the remote forests and even storm the enemy castle. In these dangerous adventures, he will again be accompanied by a loyal friend, the nine-tailed fox Lee Jin Ho.