Shapeshifters, an alien race from another planet, try to settle here on earth. They've fled their previous planet because of hostilities with the natives. The shifters have an ability to take on the appearance of any human- dead or alive- using that human's DNA. Most are peaceful and just want to live their live.
XCEL is like the FBI/CIA dedicated to hunting down shifters. Most people aren't able to tell shifters from humans, except a handful of people who have the ability to see shadows around shifters and thus identify them. Griffen is one such individual. The previous book's main female protagonist could as well. What they have in common is Native American ancestry. Griffen was betrayed by his shifter partner and thus hates all shifters.
Cam is a shifter who ends up "helping" XCEL hunt down shifters that are arsonists. However, things aren't what they seem. Cam and Griffen start out as enemies and, because this is a romance and we want a HEA, they fall for each other. About halfway through the book Griffen started to see Cam not as an enemy, but as someone who could be more.
Overall, I enjoyed this and this entertained me. Cam was a favorite character. She is honest, direct, and asked very pointed questions. I liked how she called Griffen out on his bullshit. I liked Sani and would have liked to see more of him.