Louis Mazzini's mother belongs to the aristocratic family D'Ascoyne, but she ran away with an opera singer. Therefore, she and Louis were rejected by the D'Ascoynes. Once adult, Louis decides to avenges his mother and him, by becoming the next Duke of the family. Murdering every potential successor is clearly the safest way to achieve his goal.
A distant poor relative of the Duke D'Ascoyne plots to inherit the title by murdering the eight other heirs who stand ahead of him in the line of succession.