Not what it says on the cover really. The story starts with Roman's death. He's given a choice of heaven or working to save the world against demons. He chooses to save the world and gathers a team to help. One of that team is Nina, currently overshadowing another person, she will end up in hell if she continues as she is and he has to try to convince her to leave the person she has inhabited and help him with his mission.
It's pretty predictable, but not what I expected from the blurb. It's more about Roman and his coming to terms with death and his mission. I liked the story but found it lacking in some ways, it was readable but I had no impulse to go looking for more in this world.