Mathilda, a 12-year-old girl, is reluctantly taken in by Leon, a professional assassin, after her family is murdered. Leon and Mathilda form an unusual relationship, as she becomes his protegee and learns the assassin is trade .
After her father and little brother are killed by her father's employers, the 12-year-old daughter of an abject drug dealer is forced to take refuge in the house of a professional murderer who by her request, teaches her the methods of his job so she can take her revenge from the corrupted DEA agent who ruined her life by killing her brother out of no actual reason .
