Angel Kael refuses to believe that his brother has fallen. Logan was a great guardian angel; he would never become a fallen angel. Another question that baffles Kael is who murdered Prophet Joshua of earth and why? These questions drive Kael to break one of heaven's rules - that of going down to earth to investigate. On earth he quickly discovers that nothing is as it seems and before long, he finds himself breaking a few more rules as he unravels numerous secrets and mysteries, and the most important rule that he ends up breaking is that of falling in love with a human.