But the heroine is going to, unexpectedly, discover that she will inherit after all. And another woman will learn she was the rightful heir all along.
It is a country with some strange customs in inheritance. Primogeniture and ultimogeniture where it is literally the first or last born -- the line goes extinct if they die without issue, no matter how many siblings they had. Strict matrilineal and patrilineal estates. Agnatic seniority where the order of birth in the entire family matters, so that a brother will inherit before a son unless the brother was born really late. Some with porphyrogeniture -- the children born while the parent holds the title are senior to their older siblings born before succeeding. And some with, well, semi-Salic -- in Russia, the Tsar was limited to the male line as long as there were ANY male dynasts, but failing that, the female most closely related to the last Tsar succeeded. (Since it also required that all dynasts be born to a union where both spouses were members of sovereign houses, there are those who claim the rightful Tsar is indeed a woman now.)
But that IS going to need a different name from semi-Salic. In particular because I intend to make it the rule that it converts to strict matrilineal until the female line goes extinct.