The serial murderer that had become known as the Shadow has been killed and all of the evidence points to Mira, former trace evidence analyst.
As detectives turn their focus to Mira and as she tries to avoid them, she and John Zimmer, a writing professor, try to figure out who the real killer is. As they're worried about the police and possible future deaths, they quickly realize this is about more than one murderer and the Shadow was truly a shadow to another killer.
They're in a race against time as the killer becomes angry about John's lack of attention and the relationship between Mira and John. When Mira and John come face-to-face with the killer, they discover that not all lessons are taught in classrooms. Some lessons can only be taught in the blood that has been spilled.