NEXUS is a non-linear science-fantasy/space opera series in which every book has some kind of connection to the others. Although best read in order for more background and understanding, only Ghosts of the Fallen is a direct sequel.
The murder changes everything. The Vanguard is supposed to protect against such violence, not fall victim to it. But even the so-called 'Fallen' wouldn't kill without reason. Would they?
While a vengeful inquisitor hunts the murderous cult she thought she had destroyed long ago, the Vanguard finds itself haunted by the last of the Fallen. Darkness and danger arise in both horrifyingly familiar and entirely new guises.