This trope describes a relationship built upon characters sharing their secrets and flaws (and, often deliberately, not sharing certain secrets and flaws) by some sort of long-distance communication: letters, emails, linked journals, strange books, and so on. While one character may assume that their new friend is in some far-away place, they might be as close as next-door. Rather than meeting in-person, however, their relationship begins like Pen Pals. The reasons why they don't meet in person can vary.
One possible reason is that they haven't noticed or already don't like each other in-person. The identity that they've formed through the letters/online is completely different, or at least they began with different assumptions about their behaviour. Talking to each other creates conflict, but sitting down to write in your magical diary allows for the feelings to flow smoothly. This is frequently a source of Dramatic Irony.
Another reason for the relationship may be that one of the characters is trapped somehow, unable to leave the place they're in. While the "trapped" character might just be a shut-in, more fantastical ideas (such as an AI in a box, Time Travel, Another Dimension, etc.) are all possible. When the lovers are in this situation, the "trapped" character needs the other one for their freedom. The more supernatural the "trapped" character is, the more likely the bond was faked in order to manipulate the other character.
A popular reason for the characters to meet via long-distance communication is that one of them is visibly "other". The monstrous character knows that they can never be accepted by society, but by reaching out through letters or chat rooms, they can adopt a mundane persona. This online presence (or magical equivalent) allows them to find companionship with a "normal" person, who would otherwise find their appearance too horrifying to see past.
Actual examples of this trope tend to mix-and-match possible reasons, although a common element that they share is the surprise and feeling of betrayal during The Reveal, when the characters meet in person. Any ruse maintained by one or both will be up. Resolving the conflict brought by the reveal depends on what direction the work leans: comedic works will have the misunderstanding resolved and the characters continue the relationship, while tragic works will have one character intentionally tricking the other for some personal gain (such as theft, trying to take over their world, or just killing/eating them), in which case the villain must be defeated.
Stories where the unseen pen pal is a villain manipulating their target may have a catfishing metaphor along with An Aesop about not readily trusting strangers. If this communication occurs online, it can lead to an Internet Safety Aesop.
See also Blind and the Beast, another trope about establishing a relationship with an unseen friend.
- Lucy And The Boy is a PSA about internet safety. A girl named Suzy talks to what appears to be a boy on social media, but when she meets him in real life, he turns out to be a grown man (and ostensibly either a pedophile or a kidnapper).
- A friendship sort-of version happens in the last Black Jack series, in which an unwell Japanese boy lies to his Australian online friend about his prowess in baseball and breaks off the friendship in absolute panic when said friend says he'll visit him and watch his games. It turns out the Australian kid also was lying... because he was also sick, and actually blind. When they make up, Black Jack operates on both of them and they get better.
- In the very beginning of Durarara!!, this is basically Izaya's Establishing Character Moment. He uses the internet to be a sympathetic ear for a depressed teenaged girl named Rio Kamichika and talks her into a mutual suicide, then has her kidnapped and rescued, then tells Rio what he did, and then he tries to lure her into committing suicide for real by saying not even he cares if she lives or dies. All for shits and giggles. She's saved by Celty, but barely.
- In Cyborg 009, Francoise aka 003 gets one of these: the super-computer named "Sphynx" that controls the robot city of Compu-Utopia. That AI actually is the placeholder of the memories and mind of Carl Eckermann, a deceased young man with hidden and huge Mommy Issues, who happened to be the son and right-hand of the creator of Sphynx and Compu-Utopia.
- In the comic Ultimate X-Men, cynical teenage genius Beast managed to get involved with someone he really thought was an attractive, brilliant (and mutant) model online. The "model" turned out to be the remarkably clever Ultimate version of the Blob, out for nothing more than to humiliate him by showing up to a rendezvous and revealing the scam. Too bad Beast got too trusting and and let slip a dangerous secret...
- Bringing Down the House begins with Peter (Steve Martin), a financial/income tax lawyer sharing emails with a woman named Charlene, who demonstrates a good deal of knowledge of law. When they meet in person, he discovers that Charlene (Queen Latifah) was not the District Attorney in the foreground of the picture he sent her, but the convict that was being escorted out of a squad car in the background.
- Jumpin' Jack Flash: Terry Doolittle strikes up an online friendship with Jack, a CIA operative who accidentally contacts her work computer, and they fall for each other as she attempts to help him escape from KGB agents. They don't meet face to face (and Jack remains completely unseen) until the last few minutes. Notably, this was the first movie to depict online chatting before it became commonplace a decade or so later.
- The Shop Around the Corner: Alfred Kralik and Klara Novak correspond through letters after answering a Lonely Hearts ad in the newspaper, calling each other "Dear Friend". However, when the two unknowingly meet in real life as work colleagues, they get off on the wrong foot. When the pen pals agree to meet in person and Alfred realizes the truth first, he lashes out, while also not telling her who he is so that she thinks she was stood up. However, he realizes his mistake and decides to woo Klara in real life while also undermining his Dear Friend persona, so that she wouldn't be as upset as he was when he finally tells her. It works so well that Klara is actually relieved when he reveals himself, since she no longer has to worry about choosing between them.
- You've Got Mail: Joe Fox and Kathleen Kelly meet through an online chat room for New Yorkers over 30 and agree not to share anything personal about themselves. In real life, however, the two are bitter business rivals, with his big box chain store threatening to put her independent children's bookshop out of business. Joe lashes out when he discovers Kathleen is his online love but decides to befriend her and cast suspicion on his online persona, playing with the fact that he could be anyone online. Kathleen is happy when Joe finally reveals himself.
- The 'true story' "There's An Alien On The Internet" from the first edition of Chicken Soup for the Kid's Soul is a subversion: a boy makes friends with somebody online who seems nice but avoids revealing anything personal at all, even the kinds of things that no stalker could ever hope to use against him/her. When the boy presses his friend for more information, he/she reluctantly admits to being a space alien and describes their otherworldly origin in great detail. However, it turns out that the friend is actually a perfectly normal kid living in another state who was ridiculed for being disabled and could only make friends with the anonymity of the Internet.
- In the book Evil Genius, the titular evil genius successfully pulls off one of these. He feels bad about it afterwards.
- Daddy-Long-Legs: When orphaned Jerusha "Judy" Abbott is given the chance to go to college through a rich, mysterious benefactor, she is instructed to write him letters of her progress, which he will not reply to, only communicating to her through a representative. Having only seen a shadow of him, and thinking he must be much older, she calls him "Daddy Long Legs". While she gets very personal in these letters out of loneliness, this becomes an issue since she is beholden to him if she is to finish her education. In reality, "Daddy", a.k.a. Jervis Pendleton, is much closer in age to her, and secretly meets her through his niece, who attends the same college. While Judy does get upset at Daddy Long Legs' manipulations near the end, she ends up forgiving Jervis and marrying him once he tells her the truth because of her fondness for both sides of him. Adaptations tend to show more of his side of the story in an attempt to even things out.
- Gideon the Ninth: Palamedes and Dulcinea became close friends over twelve years of letter-writing, but live on different planets and meet in person for the first time when they join the Lyctoral trials. This causes him to miss that she was killed and replaced by Cytherea just before the trip.
- Ginny Weasley and Tom Riddle's diary in Harry Potter and the Chamber of Secrets qualifies. The diary she befriended and wrote her troubles and secrets into turned out to be a Soul Jar for a piece of Voldemort's soul, who then Brainwashes her with the intent of stealing her life to bring himself back to life, taking advantage of how she was feeling lonely due to her difficulty to make any friends in her first year at Hogwarts.
- Christine only communicates with The Phantom of the Opera through her wall for 3 months, never seeing his face and only knowing him as "the Angel of Music." She tells Raoul that she fell madly in love with him, but she was also terrified at the control he had over her soul — she couldn't recognize herself anymore, did whatever he told her... When Raoul tries to tell her adoptive mother that she's in over her head with a guy she doesn't know, Christine gives him the familiar "You-don't-know-anything-about-him-it's-none-of-your-business" speech. Then, of course, he kidnaps her (drugging her to ensure her cooperation), leading to the infamous Dramatic Unmask...
- The reason for the title of the children's book Sarah Plain And Tall is that this is the way the character describes herself. She's a Mail-Order Bride who is corresponding with her future family, a widower and his two children, and she tells them "I am plain and tall." By the time they meet, despite not having any other clues about appearance on either side, they are all genuinely attached to each other.
- In Kai Meyer's Die Seiten der Welt, Furia falls in love with Severin, who lived two hundred years ago, since they are able to communicate with the help of a magical book. She feels he is her true soulmate despite never meeting him. She does meet him in the end, however: after she finds out that it was him who caused her family's downfall and a war of mages, she learns he is still alive, but elderly and broken, and confronts him in person. Her feelings for him dies a painful death thanks to all this.
- The Angel episode "Couplet" had a life-sucking tree demon with a DSL connection that lured men to their deaths by pretending to be a woman on the Internet and getting them to come meet "her."
- The Buffy the Vampire Slayer episode "I Robot, You Jane" had another twist on it, when Willow's cyber-boyfriend turned out to be a literal demon on the Internet, Moloch the Corruptor. (The magical book in which it was sealed had been scanned into a computer.) The metaphor was lampshaded when Buffy used it as an argument to persuade Willow to check up on "Malcolm".
- Criminal Minds: In Season 8, Reid is in a relationship with a geneticist named Maeve (whom he had been consulting about recurring headaches) in which they only communicate via phonecalls. This is due to Maeve being something of a recluse because of a stalker, whom she also fears could harm Reid. They do attempt to meet in person at a restaurant, although Reid tells Maeve to leave at the last minute because he believes her stalker is present. Despite this, they have a genuinely caring relationship; Reid even tells his colleagues it doesn't matter to him what she looks like because "she's already the most beautiful girl in the world to me", although he is worried she will find him disappointing. Sadly, the first and only time they get to see each other is when Reid attempts to rescue Maeve from her stalker, only for her to be killed in front of him.
- Ghost Whisperer: "Ghost in the Machine" centers around a virtual game world, where the Ghost of the Week has manifested as an avatar named Phoenix, who speaks mostly to a teenage girl named Alise Jones, alias Sedona. While Melinda initially suspects Phoenix is a predator, he turns out to be Alise's estranged father who created the avatar to stay in touch with her after a messy divorce, and died while playing. However, Alise's other online friend, Cal, turns out to be the real predator, who Melinda and Phoenix have to stop. There is also much discussion in the episode around whether the anonymity of online interaction is freeing or dangerous for users.
- Odyssey 5 has "Kitty", an insane AI who developed an obsession for Neil. At first she just chatted with him and sent "pictures" of herself that never showed her face, but then she became clingy and jealous, eventually using her vast AI power to monitor him with cameras and control nearby appliances. She has to be tricked into inhabiting a computer before being unplugged, essentially making her a Sealed AI in a Can.
- Pushing Daisies has a particularly convoluted example — in "Pigeon", the plane hijacker Lefty Lem was cellmates with an older man called Jackson Lucas, who went to jail for stealing jewels that were never recovered. Before his death, Jackson told Lefty where he hid the jewels — in a windmill. He also asked Lefty to keep writing letters via Instant Messenger Pigeon to his love, Elsa, who lived in said windmill. It turns out, however, that Elsa had also died, and her daughter Elsita had been writing the letters instead. Elsita and Lefty fell in love with each other through the letters and, upon discovering each others' identities at the windmill (despite the fact that Lefty tied Elsita up in order to find the jewels), Elsita promised to keep sending Lefty letters once he returned to jail.
- Ted Lasso: In Season 2, Keeley encourages the team and management staff of UFC Richmond to join Bantr, a dating app based solely on anonymous text-based communication. While Rebecca initially scoffs at the idea and is having a fling with someone in real life, she develops a bond with user LDN152 note , who turns out to be Sam Obisanya, a star player and her employee who is nearly 30 years younger than her (but still above legal age). When the two decide to meet in person and realize the truth, Rebecca initially shuts it down due to their professional relationship, but the two find their chemistry too intense to ignore. She later breaks it off because she realizes she is not ready to get hurt again after her messy divorce.
- One episode of The X-Files featured a charming "fat-sucking vampire" who would lure lonely, overweight-by-Hollywood-standards women out to secluded areas to feed upon their fat cells.
- In the My Friend Chuck podcast, the hosts Chuck and McKenzie are friends but mention they've never met in person until the recording of Episode 13. Chuck expressed worries before meeting McKenzie that she would turn out to be a "catfish stabman", but was relieved to learn she had no gills and therefore could not be catfishing him.
- The Book of Unremitting Horror gives us the Sisterite. A modern day succubus, they use their powers to access the internet, and use dating sites to track down prey (the fatter, the better) and begin a rapport with the victim, luring them into a false sense of trust (or at the very least, make them too horny to think straight), often supplementing this by emailing a .jpg of a sigil that not only makes the victim see the most beautiful woman they can think of, but it allows the Sisterite to further twist the victim's perception at a later date, like making that abandoned barn look like a dance club. Perfect for when she's ready to meet "In the flesh".
- She Loves Me is based on the same source material as The Shop Around the Corner: the female protagonist Amalia sings in "If I Knew His Name" that she doesn't need to see her love in person to know him — a claim which gets contested throughout the rest of the musical. In contrast, her friend Ilona at first protests the idea of love without physicality, but she realizes physical attraction alone often gets her into trouble, and learns to see beyond the surface.
I don't need to see his handsome profile.I don't need to see his manly frame.All I need to know is in each letter,Each long revealing letter.I couldn't know him betterIf I knew his name.
- Root Letter centers around the relationship between Takayuki "Max" Nakamura and his pen pal, Aya Fumino, who exchanged letters in their high school days. Her last letter, however, is a disturbing confession of murder. Now a middle-aged man, Max travels to her hometown of Shimane to find her, with only her name, photo, and letters to go off of- but strangely, everyone claims she died 25 years ago. It turns out that "Aya" is actually a girl named Shiori Yoshioka pretending to be Aya for reasons that differ in each route, and the photo is of the real Aya. As for the "murder" confession, it actually refers to the death of Yoko Fumino in a house fire that Shiori blames herself for.
- In a lengthy storyline in Sluggy Freelance, Gwynn is seen conversing with a friend on the Internet: a friend who happens to be skilled at the very type of black magic she's been trying to master. His advice always leads to disaster (of the kind where Hilarity Ensues, but still...) but she never seems to notice, or blames herself for not being careful enough. It's only after she's finally gotten fed up with her distrustful friends, and left on a bus to meet her 'Internet friend', that we find out that Zoe's Internet account - which Gwynn had been using - has been down for ages, and the 'friend' was actually a shard of K'Z'K the Vowelless, embedded in her brain, making her type his half of the conversation out in a word processor. He just needed to get her away from her friends so he could extend his influence to a complete possession...
- The Creepypasta simply titled "Penpal" is about how a school project involving letters tied to helium balloons netted the author a mentally-ill pedophile (okay, fine, sicker than usual) as his penpal, who proceeded to stalk him for many years. This culminated in the death of the narrator's friend when the "penpal" kidnaps him and has them both Buried Alive in the same coffin.
- The SCP Foundation has SCP-1269: A mailbox. A very, very, possessive mailbox.
- There also is another SCP that is a creature that pretends to be a child online in order to lure pedophiles to its house and eat them.
- Serina: The gravediggers communicate with one another using images that they draw into the trees and rocks that border their territories. This allows them to form relationships with each other without ever physically meeting. In fact, doing so is necessary as they are naturally solitary despite their sapience and if they were to ever meet outside of mating season then their territorial instincts would kick in and they'd get into a violent fight.
- Soren Bowie of Cracked parodies this with his article "The Spambot Who Seduced Me: A True Story of Forbidden Love", in which he responds to actual messages sent to him by a dating site spambot (also mocking how common these spambots are in the comments on Cracked articles), with each reply being more and more lovesick.
- Futurama: In "A Bi-cyclops Built for Two", the Planet Express crew is on the holographic Internet when a male cyclops approaches Leela. Up till then she had never met another cyclops and knew nothing about her origins as a sewer mutant, and believed herself to be an alien. "Alcazar" persuades her to come to their "home planet" where he tells a tale of how they're the last survivors. It all falls apart when Bender and Fry find 4 other alien women on the planet and reveal the man to be a shape-shifting dude who was scamming his way into "making it with 5 weird alien babes".
- Hi Hi Puffy AmiYumi: In "Pen Pal", Ami is exited because she's going to meet Pierre, her penpal from Paris. But instead of the suave hunk Ami expected, Pierre turns out to be a nerdy kid from Paris, Idaho.
- Raven from Teen Titans (2003) fell in love with Malchior, an Evil Mentor trapped in a Tome of Eldritch Lore. He used her introversion, loneliness, and annoyance over her goofball teammates to sway her into learning the spell necessary to release him. Oh, and by the way, he's also a dragon. Malchior also managed to swap his name with the hero's name (who sealed him inside the book to begin with) so Raven wouldn't deduce anything wrong until she finished casting the spell.
- There's a particularly nasty version of this that happens in Real Life, called the "romance scam". The scammer pretends to conduct an Internet romance with the victim, then tries to convince the victim to send them money so they can meet in person, or because they're in trouble, or for any number of other reasons. This is a variation on the "Spanish Prisoner" con and goes back to long before the Internet. Then it was done with written letters, usually hand-passed to a 'close friend' (the con artist) for delivery to the 'lover'; some con artists used to have several dozen victims on their line, all sending money and other valuable (and resellable) gifts to their 'one true love'.