The Darkest Days — Liza O'Connor

When the pot has too many cooks a feast can be ruined, and that's exactly what happens with Xavier and Vic's new cases. Each proves more complicated than initially thought with criminals dropping out of the sky, wreaking havoc upon Xavier, Vic, and their excellent employees. By the end, Vic threatens to open a school that teaches criminals how to stay out of each other's way.
Worse yet, a treasured member of the staff is shot in the heart while attempting to save Vic and the Queen's cousin.