Just from the brief storyline mentioned there seems to be something familiar... is this a blatant Hindi copy of the film "Man On Fire" where the storyline goes something like this.
"Man On Fire film is about a man (Denzel Washington) who loses interest in life, until he meets an eight-year-old girl. Denzel's character has been hired by the girl's father to protect her from being kidnapped. "
But watching that movie, I thought Big B should do this kind of movies as he's got tha charishma like Denzel. Luckily he's doing it !! Hope Director won'r ruin that chance.