For those readers who have not read the first book, "Sum Yung Gye: Elf Detective", I have a few points that I want a new reader to know. In the not to distance future Scientists feared a world wide Pandemic and feverishly working on a serum that not only would vaccinate people, but would prolong their lives. Not all the testing was completed when an outbreak of plague erupted in China. Fearing the worst and hoping for the best doctors in America made vaccination mandatory.
What happens was a cure, but one-fourth of those receiving the serum changed. Oh, the medical gurus tried to explain the 'Great Accident' away; they said deep down in our DNA that elves, dwarves, orcs and trolls of mythology were there. Still that didn't explain why a small portion of people now had powers, magic powers. Magic users were rare though.
The second event was national currencies became archaic. People used International Credits or just plain credits. Often for financial transactions USB sticks with Credits were used like old fashion Credit Cards. Yeah, a few remote places exchanged gold and silver but everyday commerce evolved to credits.