What is a theme in the movie?

In Shadow of a Doubt, the characters learn the importance of family. Charlie is sick and tired of her family when the film begins. She wants her Uncle Charlie to come visit so that something interesting will finally happen.

As the film continues, though, Charlie learns that family is not always what it seems. She is shocked to learn that Uncle Charlie is actually a murderer being chased across the country by police. When she wants to turn him in, though, she remembers the feelings of her family and realizes that she should put them first.

Charlie protects her family's feelings by keeping Uncle Charlie's real activities quiet. He tries to kill her, but she still wants to protect her mother and the rest of the family. In the end, she tries to solve her dilemma by forcing Uncle Charlie to leave for good, but her plan does not work quite as she'd hoped. In a last ditch effort to kill Charlie, Uncle Charlie brings about his own death.