The Soul of an Angel by F.N. Manning

In a battle between Heaven and Hell, two lovers must fight to stay together and save the world.
Frost the angel takes pride in protecting others as an agent with the Department of Supernatural Affairs. But his days on Earth are numbered when his family intends to drag him back to Heaven. After centuries of precious freedom, wishing for more time feels greedy. It’s just a shame that Nathan enters the picture right when his time as a free man is up.
Being a high school music teacher isn’t exactly glamorous, but Nathan Clinton is happy with his life. He already did the impossible once by escaping toxic, controlling parents and starting over, so stopping the demons after his immortal soul should be a piece of cake… right? Good thing a beautiful angel has offered his assistance.
When angels and demons start taking an interest in Earth and the world is threatened, Frost and Nathan find themselves in the middle of a brewing war between worlds. With the angel being pulled to Heaven and Nathan being dragged to Hell, is there any hope of them being together on this world—and also saving the Earth?