I had a story LIKE this already but it fizzled because the partner I was writing with became too busy. I, of all people, understand what it means to be TOO busy for here. Don't get me wrong, I am not mad at my partner or anything... My problem is that I liked the story idea a lot. I would like to see something like it continued.
Basically in the story, the guy angel was the teacher of a girl who didn't even know she was an angel. After something tried to attack her, at the same time the guy angel was sent to her as fast as possible and saved her.
Remember, the girl didn't know she was an angel. He has to teach her how to BE an angel, how to gain her wings, how to USE her wings and then fight off the bad things. In the meantime, the guy angel had a rule that he could not fall in love with the girl. Obviously he does. He gets punished every time he has a lustful thought or action. This is "unknown" where I will work on you with it. She has to eventually do something big or find something, go on a quest or something..
Sound interesting? Let me know. Hugs and smiles