Angels and Demons don't mix. That's what everyone believes, at least.

In the heart of 10th Century Rome, where corruption thrives and dark forces play their wicked games, Kalili, a six-thousand-year-old demon, is handed a deceptively simple task: seduce a teenage boy named Octavianus, who possesses the potential to ascend to the papacy. But her world unravels when she discovers that an inexperienced angel named Faith has been sent to execute her, an unprecedented twist of fate that thrusts them into a battle they never anticipated.

Fueled by their unusual connection and undeniable attraction, Kalili and Faith must navigate a treacherous path, their lives hanging in the balance as they uncover the shocking truth that they are the last Thirteens, destined to settle the age-old contest between good and evil. With Heaven and Hell both seeking their destruction, they must harness newfound powers, evade sinister adversaries, and unravel secrets that could alter the very fabric of existence.

The consequences of their choices may change the course of history, as they embark on an epic journey in a gripping tale of love, destiny, and the ultimate battle between light and darkness. This is the beginning of a mesmerizing saga filled with unexpected alliances and discoveries, propelling them toward an uncertain and perilous future.