Children of the Night — E.W. Skinner

Sybille Malone lives in an overpopulated Manhattan, Region One, of Global Good 2202. Their society is the fulfillment of utopian ideals developed by the surviving masses of 2100. Seventeen-year-old Sybille is a resident of Dayshift and longs for a Nightshift boy known only as Mark. Distraught by Global Good's restrictive culture, Sybille is desperate until she finds a relic of a past civilization. The discovery of Blair's diary sets off a chain of supernatural events that not only affects Sybille's close relationships, but has Global Good scrambling to find the culprit.