The reader is half human, she gets her powers from her mothers side. Controlling the Elements, but has kept it a secret.
One day she meets Tony Stark and he takes a shine to her, he takes her back to the Avengers Tower and she has been working with the Avengers ever since.
She meets Thor and falls for his boyish charm and his (eh hem) heavenly body.
But mostly because he had a beautiful soul that outshone the stars.