The movie centers on a twelve-year-old Natalie Portman portraying Mathilda, a girl living with an abusive stepfather, stepsister, mother, and four-year-old brother. She doesn’t have affection for any of them except her younger sibling. One day, returning from grocery shopping, she discovers that corrupt DEA agents have murdered her entire family. Among these agents is Stansfield, portrayed by Gary Oldman. Finding safety in the apartment of a neighbor, Léon (Jean Reno), whom she had previously befriended, she learns he’s a professional killer. She proposes an arrangement: she'll manage his living space with chores if he teaches her how to avenge her brother’s death. Despite the unusual premise, the connection between Léon and Mathilda remains pure, and their interactions feel genuine. Mathilda’s understanding of sexuality is just beginning, and her exposure to a dark side of life—her stepfather was involved in drug dealing—means she might not be as naive as most girls her age; however, Léon refuses to exploit this. This allows the narrative to concentrate on their platonic bond, how they influence each other's lives, and the connection that forms between them. While it may seem improbable that a young girl would accompany a hitman on his assignments, Léon makes sure she’s only involved in fairly standard jobs with predictable procedures. He leaves her behind when the missions are more complicated. A sense of humor is present throughout the film, but it's important to remember that it exists within a world of corruption and avarice, and things aren’t always pleasant or carefree; graphic violence is shown. Jean Reno delivers an excellent performance as the exceptionally kind yet calm hitman, whose entire perspective on life is altered by young Mathilda, also wonderfully portrayed by Natalie Portman in her debut film role. I haven't read it myself, but I hear that Eppie has a similar impact on Silas Marner, as described in George Eliot’s novel. Gary Oldman’s acting felt over the top; this was the only disappointing aspect of the movie, though it didn't significantly detract from the overall experience. I suggest seeing it.

Source on TMDB