My idea was this

Plot : Armies of Heaven have been fighting with heavens for 4,670 years, Lucifer commanding the armies of hell, his locked away form not able to battle as he was locked away. But when the humans decide to free the devil seeing maybe there might be a way to stop the armies from fighting. The humans find a book (A book Lucifer once wrote that had the magic to release him) the humans find a way into hell and free the archangel and rush out, But only problem Lucifer distaste for the human race got them into deep trouble. Can the humans help change the fallen Archangel to change his mind and end the bloody war ? Will gods favor rest with the humans, will he grant his fallen son a chance to prove himself worthy of coming back to heaven.