Sean Nault is a detective in a world just like ours — except that magic rules the day and almost nothing is known of science. Someone is killing people using a gun that can project a metal slug into the victim's body, the lead revealing no trace of magic when subjected to analysis. Nault is in charge of the investigation, but is somewhat controversial for his non-use of magic in investigations, such as relying on his own perceptions to tell if a suspect is lying rather than using truth spells.