Mathilda (Natalie Portman), a young girl from a bad family in the projects comes home one day to see her entire family, including her baby brother, shot in cold blood by a group of hitmen led by a man named Stansfield (Gary Oldman). A chance acquaintance with the next door neighbor, a quiet man Leon (Jean Reno) saves her from falling victim to the hit as well. Once Leon takes her in, he feels responsible for her, and she becomes his companion for the rest of the story. It does not take Mathilda long to figure out that Leon is really a highly trained assassin, and although her child-like excitement at the idea is a source of some friction between them, their bond grows stronger. Mathilda winds up teaching Leon to read, while Leon teaches her a little about his craft. The movie culminates with the final confrontation between Leon and Stansfield.