Five characters, with gifts they do not fully understand, are mysteriously brought together to battle growing pockets of darkness throughout the world. When the Harbingers team is sent to Mexico to search for a fairy, Andi is thinking of pretty wings and magic wands until they are shown the dead body of an actual winged creature. From where did these things come, and why has there been no sighting of them until now? When someone reminds them of an age-old prediction, the "fairies" seem much more sinister than charming.