Hourglass is the third instalment to the Evernight series following Stargazer. The three books are written by Claudia Gray which is a pseudonym for the New York-Based Author Amy Vincent. The third book combats vampires, wraiths (ghosts), betrayal and of course love. The main character, Bianca Oliver is living with her rocky, shaky, strong, sturdy and passionate relationship with the head man, Lucas Ross. But Lucas is also a member of the ancient vampire hunting group Black Cross.