Since the beginning of time, angels and demons are forbidden to be together. God, Lord of the Kingdom of Heaven, and Lucifer, Ruler of the Kingdom of Hell, dictated a law for both species: angels and demons cannot fall in love. It has been like this for a long time. But one day, an archangel named Gabriele fell in love with a demon named Demetria.

To be together, they disobeyed their respective kings and combined, creating the famous Big Bang that gave birth to the planet now called Earth.

God and Lucifer punished the two lovers by separating them and condemning them to only look at each other for eternity, since all angels and demons are immortal. Their union started a very ancient and powerful curse that not even God and Lucifer could ever undo. This affected not only Gabriele and Demetria but also their respective descendants. God and Lucifer erased Gabriele and Demetria's memory and everything that had happened, so that no one could ever know about the terrible curse. As the years passed, Lucifer and God discovered that, one day, an angel belonging to Gabriele's bloodline and a demon belonging Demetria's descent would unleash the curse that would strike not only them but every other demon and angel.