Poor little RJ has been used and abused by everyone. She hasn't been wanted, needed or cared for since her dad died several years ago.
One day after a tragic encounter, She follows a bird, she believes to be her father reincarnated, farther into the cave. As she goes deeper and deeper into the earth she sees a light. She heads towards it. But falls down a cave shaft. She is thrown into a white room.
God has a mission for her. She is to collect orbs all around the world in order to close the door to Hell. One by one they will be absorbed into her body, completing the Key.

She is given a companion to protect her. If she doesn't get these orbs in time the devil will be released. He wishes to destroy humanity in order to create his own demonic race. She doesn't know if the people deserve to live after how they treated her.
Angel knew that by taking this job that she would be united with her soulmate. And it would mean she would not be able to be reincarnated with her in the future. Angel keeps the secret of their fate from RJ because she wants her to be happy for once in her life.