THE NEXT COUPLE OF DAYS were strange. The other novices and I might have had the flashiest graduation, but we weren’t the only ones finishing our education at St. Vladimir’s. The Moroi had their own commencement ceremony, and campus grew packed with visitors. Then, almost as quickly as they came, parents disappeared—taking their sons and daughters with them. Royal Moroi left to spend their summers with their parents at luxury estates—many in the Southern Hemisphere, where the days were shorter this time of year. “Ordinary” Moroi left with their parents too, off to more modest homes, possibly getting summer jobs before college.

And of course, with school wrapping up for...