A mysterious note from a stranger changes the plot in some way. Generally, it is shoved under or into something such as a locker, postbox, or a door. If the recipient sees the note drop on his mat and dives for the door, he will occasionally catch the messenger in the act of posting the note; however, the messenger usually leaves so fast it's as if he teleported. Can be anything at all, for example:
- A clue from an anonymous source
- A note from a past or future self
- A revealing tape of some kind
- A threat of some kind
- Ransom demand
Examples:Anime & Manga
- In Ore-sama Teacher, both Mafuyu and Hayasaka receive notes in their lockers saying "360 degree warning". This presages the appearance of a new character, a wacky fake 'ninja' who is trying to destroy the Public Morals Club.
- So many times it's not even funny in Harry Potter and the Methods of Rationality
- Murder by Death. While Sam Diamond and Miss Skeffington are in their room, they hear a ticking sound. A note is slipped under their door that says, "That ticking sound is a bomb that will go off in 30 seconds. Signed, The Murderer."
- The Incredibles. The "note" is in the form of a digital tablet with a video message inviting Mr. Incredible to do secret superhero work.
- In Unsane, a horror/thriller author receives one about a series of murders related to his latest book.
- Memento: The hero receives a few of these. Some of them from himself, since he suffers from anterograde amnesia.
- Home: Frank Money receives a note that says, "Come fast. She be dead if you tarry." This causes Frank to start his journey home to save his sister.
- In The Hound of the Baskervilles, Sir Henry Baskerville receives a message consisting of words cut and pasted from the London Times warning him to stay away from the moor (where Baskerville Manor was).
- Mysterious poison-pen letters (together with pranks and outright vandalism) are part of a plot against Shrewsbury College, Oxford in Gaudy Night.
- A couple of these appear in Aunt Dimity Takes a Holiday. The notes' author employs the classic pasted-letters-cut-from-printed-material technique.
- In The X-Files, Agent Mulder repeatedly receives revealing documents on various conspiracies from his informants. They try to be sneaky about it.
- In an episode of Magic City, an envelope is shoved under the door. When opened, it contains a photo with "$20,000" written on the back. The photo shows one of the heroes in bed with a mobster's wife and is clearly an attempt at blackmail.
- Mysterious notes or objects are often the catalyst for Scott Wolter's investigations on America Unearthed.
- In WHO dunnit, Hardboiled Detective Nick Spade receives an unsigned note asking him to meet someone in the basement of Tony's Palace. It's actually a setup for an ambush by the murderer.
- Silent Hill 4: Henry can receive messages from the dark world if he slides blank pieces of paper under his door. Better go check on your neighbor!
- The Dream Machine has it's main plot started by one Viktor finds in his new apartment.
- World of Warcraft: At the start of the Mists of Pandaria legendary questline, you receive this conveniently named item, indicating that the last of the Black Dragons wishes to recruit you to save the world.