Part of the appeal of Nancy Drew through the decades has been the way she has continually been updated while remaining essentially the same. The problem with this movie is that the updates are poorly chosen, awkwardly inserted, and inappropriate for its intended audience.

In the original books, Nancy’s mysteries were usually about lost lockets, secret codes, maybe a kidnapping or some attempted harm that Nancy was able to prevent just in time. In this film, the central puzzle is the murder of a film star, and the plot centers on an out-of-wedlock pregnancy kept secret even from the father. This is an incomprehensibly poor choice in a movie intended for children. It also a poor dramatic choice, undercutting the movie’s plot, tone, and style and throwing its story off-balance.

In the opening scene, Nancy (Emma Roberts) crisply captures a couple of bad guys (watch for “Saturday Night Live” alum Chris Kattan). They may think they have captured her, but she soon turns them over to the grateful local cops, who have come to rely on her for their toughest cases. But all of that is coming to an end. Nancy’s father (Tate Donovan) has to go to Los Angeles for several months on business and she is going with him. And after solving that last mystery had her dangling off a rooftop, Mr. Drew makes Nancy promise that she will take a break from crime and just be a normal high school girl in their new city.

She does not tell him she selected their new home because it had a mystery for her to solve. Many years ago, a beautiful and successful actress was murdered there and left some clues behind. And there is a caretaker who may know something as well.

All of this is much more important to Nancy than lesser mysteries like how to make friends in her new school. But that retro attire she whipped up from her mother’s old patterns pretty much acts as a classmate-repellent, so she has to find a way to make some friends who like her the way she is.

Roberts (daughter of Eric and niece of Julia) has a natural elegance, poise, and focus. She fits well in the role and she looks sweetly chic in her classic wardrobe. As in the books, Nancy is a clever, determined, and spunky detective who can be fascinated by crime and still have an air of innocence. When it comes to boyfriend Ned Nickerson (Max Thieriot), she is barely aware that he might feel anything more than friendship or expect her to make him a priority. This makes her focus on the illicit romance of a long-dead movie star all the more awkward. So is a possible jealousy subplot involving Ned and an annoyingly precocious 12-year-old named Corky (Josh Flitter). A surprise cameo from a big star is just a distraction, adding nothing to the sleuthing or new kid in school storylines.

Young detectives serve as inspiration and metaphor for children trying to puzzle out the mysteries of the adult world. Seeing someone their own age understand and explain what is going on to grown-ups is highly satisfying for children. But here the uncertain shifts in tone from sincerity to almost-camp and the inappropriate subject matter make the unsolvable mystery just who this movie’s audience was intended to be.

Parents should know that although handled in a low-key way, the themes of this film include murder and out of wedlock pregnancy. There are some scary moments, including what appears to be a ghost. Nancy also takes some risks and breaks some rules.

Families who see this movie should talk about why some of the other girls thought Nancy was strange and how that affected the way they treated her. How should we treat people who are different? What made them change their minds? Who in the film was jealous, and why? They might like to think about the changes Nancy has had to make over the years. Even in the constantly-reissued books, Nancy does not drive a blue roadster anymore. She uses the internet in her sleuthing. Vestiges of racial and gender stereotypes have been eliminated. What other changes do you think they have made or should make?

Families who enjoy this movie will also enjoy reading the books. Nancy Drew now appears at different ages in separate series designed for ages eight to early teens (with more mature material than the original series). She even appears in video games.

For more background on the history of Nancy Drew, try Girl Sleuth: Nancy Drew and the Women Who Created Her and Bobbie Ann Mason’s The Girl Sleuth. They will also enjoy Agent Cody Banks and an earlier version, The Original Nancy Drew Movie Mystery Collection, played by Bonita Granville.