As the battle for Heaven wanes, archangels Michael and Lucifer are concluding their own struggle. Michael manages to strike Lucifer down, drag him to the edge of Heaven, and cast him out. But in their titanic struggle, the key of the Abyss is torn from Michael's belt. All Michael can do is watch as Lucifer tumbles toward Hell and the key spins toward Earth. Hundreds of years pass before Lucifer learns that the key of the Abyss has been lost on Earth. He sends one of his fallen brethren to Earth to find the key, release the biblical plagues from the Abyss, and lead his demonic armies through the open gate to destroy humanity. When Heaven realizes that Lucifer has sent someone to find the key, they send one of their own to Earth to reclaim it. As the fallen archangel, Jetrel, and the archangel, Raiel, continue their frantic search, they begin to see sides of humanity they never expected. Jetrel battles a newly found conscience, while Raiel begins to find pleasure in immorality. With Jetrel and Raiel struggling to decide where their allegiances now lie, the fate of humanity remains uncertain...