yunho and jaejoong are angels whose mission is to guide souls to either heaven or hell. yunho, a black angel, guides corrupted souls to hell, while jaejoong, a white angel, guides pure souls to heaven. Both have to work together as partners to accomplish their task. However, God cannot forgive black angels for their accumulated sins, and only gives white angels the power to reincarnate. Though yunho develops strong feelings for jaejoong, can he escape the cruel fate that God has given him?