Nikkita Sampson, a demon forced to live as a human until she corrects the universal imbalance she has caused, takes on the role of a serial killer dubbed by the FBI as 'the Quantico Killer.' Her demonic powers have become limited, but she still manages to maneuver about in a semi-demon form when it is necessary for her to kill and to feed. The only way for her to safely leave the human realm behind is to destroy all of those who know what she truly is and who are in constant attempts to open a portal between their two worlds. The only problem is that this secret society is of unknown...