Season One
When the Halliwells trigger the re-emergance of their magik powers, Leo is sent to watch over them. He is their 'Whitelighter', a kind of guardian angel for witches. He acts as their handy man, and falls for Piper, which is against the rules. Whitelighters are supposed to keep their identity secret, even to those who they are watching over, and falling in love is totally out of the question.

Season Two
Leo and Piper's feelings grow stronger, and things get more complicated with the knowledge of Leo's true identity. He eventually get's his 'wings' clipped, and is rendered mortal, unable to help the girls when they get into trouble.

Season Three
coming soon.....

Season Four
coming later....