Buffy the Vampire Slayer: Reunion (Book One of the Reunion Trilogy)

Nearly eighteen years after the destruction of Sunnydale, Buffy Summers has settled into a new life and made peace with her past. When she discovers that enemies both old and new are massing for a nefarious purpose, she and her loved ones find themselves struggling not only against the rising evil, but also with the question of whether they should step away while they still can.