The protector

In the paranormal world, when the humans die they turn into Angels but if they do something bad when they are human or Angel, they will turn into a Fallen Angel and get sent back to Earth, where you get an assignment and that assignment is a human that is in danger. That human that you are assigned to must be protected by you at all costs. There are three rules.

#3. Don't tell or expose US
#2. Don't harm or endanger the human you are protecting
#1. Don't fall in love

If you break any one of these rules, all of the evil spirits and beings in the paranormal world will come after you and your assignment and hunt you both down.

You have been warned.