Everybody in a small town used to have a normal life until something bad happened in their hometown long time ago. So years have passed, everybody from the town decide to keep it a secret.
A terrible secret that nobody outside the town must know. The visiting protagonist slowly begins to suspect that something is wrong and they will try to stop the main antagonist before it is too late.
Everybody in a small town is in on a secret. A terrible secret that nobody outside the burg must know. The visiting protagonist slowly begins to suspect that something is wrong.
Such towns are often located in "Lovecraft Country" from the works of legendary sci-fi horror novelist and poet H.P. Lovecraft. If the terrible secret is covered up with a sweet veneer this trope is connected to its sister notions "Stepford Suburbia" and "Uncanny Village" involving a seeming a friendly community bearing a dangerous mystery no one talks about.
If it is big enough — say, a country or more — then there lies an "Empire with a Dark Secret". Also note that the secret does not have to be supernatural; it can be something as mundane as a murder coverup.)
- In the Silent Hill universe, the titular ghost town founded by a religiously-crooked group of dangerous cultists known as The Order and harboring a very twisted dark world within its silent foggy atmosphere. Silent Hill: Homecoming introduces another tragic dark town, Shepherd's Glen (founded by 4 families whose ancestors were former affiliates of the Order by still fearing the wrath of their parent "faith"'s God), this time with additional child sacrifices.
- In Toy Story 3, Woody and the gang wind up in a day care that looks like paradise. The toys (led by a fluffy stuffed animal named Lots-O' Huggin' Bear) are all friendly, there are always lots of kids to play with them so that none of the toys ever get outgrown, and there is a repair ward that keeps the playthings in tiptop shape. However, their dark secret is that, in order to stay in the older kids' playroom, the ruling toys regularly sacrifice new toys to the toddler's playroom, where too-young children bash and beat toys until they are destroyed and thrown out.
- In Children of the Corn 666: Isaac's Return, the citizens of former ghost town Gatlin act normally, but gradually drop it until it was time for the final prophecy.
- Implied in the Friday the 13th (2009) remake, where at least one resident was shown to be aware of Jason Vooorhees living and killing in the old campgrounds. This is markedly different from the originals, where the residents of Crystal Lake did not seem to know exactly what was going on at the camp, but were pretty clear in their warnings to outsiders.
- In Freddy vs. Jason, many adults in Springwood, Ohio know of Freddy Krueger's nightmarish killings happening only in the dreams of the local children and teenagers, but have conspired to conceal this from the town's youth to starve him of the fear that gives him power over dreams. Jason comes to Elm Street at Freddy's instigation, so his killings will revive old stories about the Springwood Slasher and restore Freddy's dark powers.
- In John Landis's An American Werewolf in London, the small English town of East Proctor's Dark Secret is, unsurprisingly, a werewolf.
- Author Stephen King calls this "The Peculiar Little Town" and has confessed that he has a weakness for writing stories of this type (among them Children of the Corn, Rainy Season and You Know They Got A Hell of A Band).
- His best known peculiar little towns are Derry (IT) and Castle Rock (good number of stories including Needful Things), both in Maine, which tend to redline the "weird-s**t-o-meter" on a regular basis. In the end, Derry is destroyed after the defeat of a sinister force residing there, which is probably for the best. Castle Rock is destroyed by a visiting evil that took advantage of the secrets and flaws of many of the townspeople so that it could take their souls.
- Haven, which is near Derry, in The Tommyknockers. It starts off as a normal town, but becomes this trope when the ancient alien spaceship buried the town's nearby woods is first unearthed and slowly makes everyone crazy and obsessed with it.
- Jerusalem's Lot from Salem's Lot had a family of gangsters that worshiped demons and consorted with vampires. One of these vampires comes to town and then it really has a dark secret. By the end, the whole town is undead except for the protagonists, who burn the town down and leave. A couple of later short stories by King reveal that burning the Lot down only temporarily halted the vampires. And it was hinted throughout both the novel and the prequel story that we still do not know the worst of its secrets.
- Willow's inhabitants in Rainy Season try to warn people about their annual "bad weather problem", because warning the newcomers is part of the tradition. As is the inevitable death of the newcomers — always a young man and woman.
- Ludlow has the secret of the real Pet Sematary, the Wendigo, and what lies beyond the said cursed place's Deadfall.
- Little Tall Island has a couple. In Dolores Claiborne, it was the decades-long mystery following the death of Dolores' husband. In Storm of the Century, it is the fact that the entire town surrendered one of their children (the police chief's son, no less) to a visiting demonic wizard to save themselves.
- In the My Little Pony animated series, Starlight Glimmer's town, where every pony had the same equal sign cutie mark
- In Stranger Things, the town of Hawkins, Indiana has a secret government laboratory where it housed a portal to an alternate universe "The Upside Down," which is a darker, scarier version of Hawkins.