When Lucifer is your brother, all hell can break loose. The ex-archangel Gabriel, now living in Riverside, California, struggles to find his new normal. However, a surprise visit from his older brother, Michael, brings disturbing news. There's a key to the backdoor of hell and if their errant brother, Lucifer, finds it, he'll unleash a horde of blood-thirsty zombies on humanity. Zombies? Seriously? Can Gabriel not get through his identity crisis first? Abby Campbell is a newly minted Keeper—the guardian of one of the heavenly Books of Knowledge. The ancient relic might contain the cure to save her dying mother, but searching the pages could reveal the key that Lucifer seeks. As Gabriel and Abby, along with his former-demon lover and her all-too human boyfriend, chase the clock to stop the ravenous zombie horde, they face betrayal, heartbreak, and familial dysfunction of the highest order. Even the best-intended choices have consequences while the fate of heaven, hell, and earth hangs in the balance.