Josh Hartnett and Bruce Willis are partners. Hartnett doesn't know Nick Fisher, he found the name in a bookies book. Fisher is none other than the man at the beginning of the movie (the one that Bruce Willis killed at the airport). Hartnett is the one that killed Morgan Freeman's son. Hartnett is getting revenge on Freeman and Ben Kingsley because they killed his parents twnety years ago, in the story that Willis told at the beginning of the movie. The kid in the story is actually Josh Hartnett. Willis was the one holding the gun at him, but he didn't kill him. Hartnett kills Freeman and Kingsley. Bruce Willis shoots Lucy Liu because she took his picture, but Hartnett warned her and she was wearing a vest and had fake blood. Also, Det. Brikowski is the one that killed Hartnett's mother, so Hartnett kills him. Hartnett used the name Slevin because Slevin was the name of the horse at the beginning of the movie.