Strange Changes

Three months after I lost my job, I inherited my grandfather's "agency" and found out that it was not selling houses, but helping ghosts solve their "posthumous affairs": Help a starving man order a paper-made Manchu banquet, and help a lovelorn man burn crying idol posters... I thought I was earning "KPI bonuses from the underworld", until a female ghost wearing a Republican student uniform came to my door and said that my grandfather owed her a "betrothal gift" of three hundred years, and that she would either pay back the money or I would marry her on my grandfather's behalf. Help, I just want to make some money in the world, how come I have become a "sale champion reserve" in the underworld?