On the way from his estate to Saint-Marco, the Count de Brienne disappeared without a trace, and with him disappeared a cart with precious gifts for the temple of Saint Lourdes and the detachment of ten knights accompanying him. The king instructs Baron de Segur to find out the fate of the missing count, and at the same time pay his respects to the old constable of the kingdom, the Marquis de Liancourt, with whom Mark has a long-standing, difficult relationship. Carrying out his orders, Mark finds himself drawn into a series of risky and sometimes deadly adventures. He will not only have to catch a gang of ruthless robbers, but also learn the fatal secret of his own origin, which can change his life and destiny.