Snooping Little Kid

""Well, well, well, what have we here? A snooping little girl!""

- Any MAD Agent, Inspector Gadget

There's a kid, usually a preteen, who thinks something suspicious is going on. Those men talking in low voices, that guy who keeps sneaking away... what are they up to? Enter the Snooping Little Kid.

The Snooping Little Kid will hide where the bad guys are and try to listen in on their conversations, usually picking up just enough information to prove that something sinister is going on, even if the kid doesn't know exactly what. That often is what kickstarts the plot, or at least advances it into high gear.

Sometimes the Snooping Little Kid is spotted, or manages to make a noise that draws the attention of the bad guys. In that case, the kid will either make a narrow escape, or end up being captured and Bound and Gagged.

Common trope in adventure or mystery stories, or stories with such themes, especially when aimed at children. Happens in books as well as cartoons, TV shows, and movies.

If the kid does more investigative work than just eavesdropping, they're a Kid Detective.

Examples:

Anime and Manga

 * Ayumi, Mitsuhiko, and Genta in Detective Conan. They style themselves Kid Detectives, but aren't quite up to snuff without Conan or Haibara helping them. They do show potential though, when they try to beat Conan to solving a mystery. They still need help, but Hattori mostly dropped hints for them to work it out themselves. They also provide the occasional Eureka Moment.
 * It could be said that Conan himself is this, at least from the perspective of the other characters.
 * Spridle and Chim-Chim from Speed Racer.

Film

 * In Little Women's The Movie of the Book, Beth (played by Margaret O'Brien) and Amy (played by Elizabeth Taylor) fulfill the role in the Christmas party (which is actually a mix between the Christmas party of the book and the parties Meg attends when in the moffat household). Then they overhear some Gossipy Hens speculating about their belief that Marmee wants Jo or Meg to go Gold Digger mode on Laurie, which causes both girls (an specially poor Beth) to have Heroic BSODs...
 * Being adapted from the book, Harriet the Spy.

Comics

 * A curious example: There used to be a long series of Disney Comics rooted in their Little Hiawatha shorts, who were basically family sitcom adventures about a little Native American boy. Whenever there were enemy tribes, dishonest white traders or greedy settlers wanting to steal stuff off tribal lands about, Hiawatha (who is eight, tops) and his little sister Sunflower would be the only ones who would notice. Appearently Adults Are Useless regardless of your ethnicity.

Literature

 * Subverted in A Song of Ice and Fire when Arya Stark witnesses a nefarious conversation between two mysterious figures. When she tries to tell this to her father, he disbelieves her of course. However Arya isn't able to do anything with the information as other (different!) plots reach their conclusion. Of course, she could've been a bit more credible if she didn't mention a hall of monsters and the wizard.
 * Subverted earlier with her brother Bran, he overhears the queen and her brother's plan, and even sees them having sex. He gets spotted and thrown out the window he was perched on, putting him into a coma. An assassin almost kills him in his unconscious state too.
 * Lyra from the His Dark Materials trilogy does this repeatedly.
 * Happens all the time in Animorphs with the kids snooping on people while in some small morph.
 * Subverted by Malicia in The Amazing Maurice and His Educated Rodents, who is clearly familiar with the trope, but very bad at the actual sneaking around. People stop what they're doing to watch her sneak around.
 * Children's book and later movie Harriet the Spy. She's not so much a spy as a snoop, and snoops for the sake of it.
 * Harry, Ron and Hermione fit this pretty well in the first two or three Harry Potter books.
 * In the fourth book, Rita Skeeter's role was originally going to be filled by Ron's annoyingly superior second-cousin, who would have taken snooping to a new level of art.
 * The thirteen year old protagonist of the Trixie Belden series was not exactly 'little', but did often stick her nose into places that required an adult.

Live Action TV

 * Ruthie from Seventh Heaven often took to spying on the older members of her family, until she became a teenager.
 * Every CBBC Sunday afternoon drama of the 1980s featured a young protagonist snooping around and stumbling on the Big Bad's plan.
 * The Mystery Science Theatre 3,000 episode featuring Angels Revenge (a low-budget feature film knockoff of ~Charlie's Angels~) spoofs this trope. In the scene with a meeting of the film's several female protagonists, the heroines are making plans to launch an assault on a drug cartel, when a young blonde girl character who hangs out with them (probably added for comic relief) bursts into the room, acting excited at the plan. In the film itself, the heroines think this is cute and amusing, but one of the audience members remarks, in a menacing voice imitative of more sinister characters, "Kill her!"
 * In the Twilight Zone episode "Caesar and Me", the nosy niece of the apartment landlord spies on her aunt's tenant, which leads to his arrest.
 * There must be a million German TV shows and movies for kids that feature this trope. One example is Tom Turbo, in which some Snooping Little Kids, often with the same name as the kid actor who plays them, stop the villain and their criminal scheme. This even comes complete with many Bound and Gagged situations.
 * Bronson Twist often takes on this role in Round the Twist, particularly in Season 2. The Twist kids as a whole get called this at least once by Mr Gribble.

Video Games

 * There's a quest chain in Final Fantasy XI that involves the Star Onion Brigade, a gang of Snooping Little Kids who operate out of Port Windurst and fight for "Truth, justice, and the onion way!", which seems to mostly involve pestering local criminal mastermind Nanaa Mihgo.

Web Comics

 * Antimony from Gunnerkrigg Court carries around a set of lock-picks (and knows how to use them) for this very purpose.
 * She does quite a bit of snooping even without lock-picks, including, once, fooling a guard-bot into believing she was a robot using a headband with antennae and "I am a robot." It worked. Robots in Gunnerkrigg Court are notoriously gullible.
 * Jack gone out exploring the Court "all the time". At least, until in Chapter 19 he demonstrated his discovery of an Ether Station to other students. Rather unfortunately for him, at the same time as Zimmy (who did have a good reason) found it too.

Western Animation

 * Penny from Inspector Gadget is a perfect example of this trope. She is always sneaking around the enemy's latest hideout, trying to discover their plans and stop them. She would sometimes narrowly escape capture or detection, and other times would get caught, at which point her captor would utter the quote at the top of the page.
 * Jade in Jackie Chan Adventures.
 * The main characters of Scooby Doo were treated this way, despite the fact they clearly weren't little kids . Hanna-Barbara made up for this with actual kids in most of their subsequent Scooby-clones (See: Clue Club, The Amazing Chan and The Chan Clan, and the 80's cartoon called A Pup Named Scooby Doo that followed the same characters when they were children.)
 * TJ in the Recess movie.
 * In An American Tail, Fievel was being a Snooping Little Kid when he snuck into the secret hideout of the cats and found out Warren T. Rat  He ends up captured and locked in a bird cage.