Batman: Bruce Wayne lives in Batman's attic!
Some character a Rebellious Princess, an alien, The Chosen One or the Mad Scientist's Beautiful Daughternote is on the run, homeless, out of options, and needs a place to hide. It becomes the duty of the first available Ordinary High-School Student they come across to stash the hero in their basement/garage/attic/bedroom until they Save The World/defeat the Big Bad/find a portal back to their Magical Land.
The rescuer, whether enthusiastic or reluctant, quickly runs into a big problem. Because they are not a victim of Parental Abandonment, they have to keep up a charade of hiding the character from said parents. Family members start to notice that the character's spending a lot of time in their room, acting rather snippy about people going in there, stashing food, and apparently talking to themselves. They will make some quick excuses about practicing lines for a school play.
Meanwhile, the hidden character isn't much help, being prone to doing strange things having to do with their origin, or falling in love with their protector's sibling or friend, or being pursued by one of their own, or being incapacitated.
When the character is eventually found, a quick Secret Identity, Unpronounceable Alias, or Line-of-Sight Alias will be conjured on the spot, along with an unusual job title to explain their strange outfit. If female, the hidden character will frequently end up as a maid.
As you would expect it is also a popular concept in fanfictions. Mostly in the form of the author him or herself finding his/her favorite and beloved character entering the real world from their media of origin (book, tv, comic, etc.) and befriending them.
The Trope Namer is the Batman: The Animated Series episode "I've Got Batman In My Basement", which revolved around a group of local children hiding Batman from the Penguin as he recuperated from a heavy dose of poison. The production team does not think too highly of the episode, citing their distaste for excessively kid-friendly plots as well as the bumbling antics of the villains.
Subtrope of Sent Into Hiding.
- Rukia initially hides in Ichigo's closet in Bleach and raids his sisters' wardrobes for street clothes. Ichigo was rather surprised when he found out. Once the whole charade becomes a moot point, she continues to live in his closet. Apparently she just likes it in there.
- Haruko in FLCL ends up sharing a bunk bed with the main character while masquerading as a maid. This could be considered an inversion from the standpoint that Naota's father invited Haruko in, despite Naota's complaints, so one of the critical points to this trope (hiding it from his parents) does not play a part. Nor is he particularly trying to help and care for her.
- In Rurouni Kenshin, Seta Soujiro hid the fleeing Shishio. When Soujiro's abusive family (he was an illegitimate child) catch on to the missing bandages and food, they corner the boy in an attempt to kill. He snaps.
- Digimon touches this theme a lot when the action is set in the real world, with the Digimon usually acting as soft toys. The parents usually find out the truth eventually.
- Digimon Adventure plays the trope straightest with Izzy to the extent that his parents become concerned that "one day at camp" changed him so much. They're a little more bewildered when Tentomon ends up botching it too.
- Subverted in Digimon Savers. Masaru tries make a big point to Agumon that he must not, under any circumstances, be discovered by his family... only for both of them to botch it thirty seconds later. Mom took it pretty well, actually. Considering DATS is the reason her husband disappeared, it's not really surprising.
- Basically averted in Digimon Tamers. Terriermon does play the part of a plush toy (and gets subjected to play dates with Henry's baby sister Suzie), but Renamon is rather skilled at not being seen and she goes off on her own half the time. Takato makes an attempt at this trope with Guilmon, but after about a day he realizes it's not going to work so he finds an abandoned shed or something in a nearby park that Guilmon can live in.
- Pretty much the entire run of Detective Conan, where the main character has de-aged ten years and lives with his She Is Not My Girlfriend classmate until he can change back. Which he does, briefly, on several occasions. Naturally, more and more people are discovering his secret, including a confidant of the Big Bad.
- Also befalls Deadpan Snarker Ai Haibara, aka Sherry.
- In Yes! Pretty Cure 5, Coco lives in Nozomi's room at first. After an incident involving Nozomi's mother, however, the girls immediately go find him another place to live where his presence won't be as questionable.
- In Kimi wa Petto, Sumire keeps a homeless young man named Takeshi, or "Momo", in her house as her "pet". To keep her boyfriend (and dog-lover) Hasumi in the dark, she has to borrow her friend's actual pet dog when Hasumi wants to see "Momo", and Takeshi pretends to be her distant cousin whenever Hasumi unexpectedly drops by.
- Hasumi later has his own Batman when Shiori Fukushima moves in, threatening to tell Sumire about the night they spent together if he kicks her out(nothing happened, but Hasumi doesn't remember that).
- A good deal of humor in Code Geass (especially in the side stories) stems from Lelouch having to hide C.C. in his room. In one audio drama, he and Suzaku have a conversation sitting on his bed while she is literally under the bed. Kicking. Lelouch says it's a custom alarm clock.
- Sonic X features Chuck, Chris, and their two servants hiding Sonic and his friends from the world, Eggman, and Chris's parents. At least until Eggman's land base is destroyed and the world becomes aware of their presence.
- In a Hayate the Combat Butler omake, Izumi saves the title character from spending a night out in the cold (instead of Hinagiku in the main storyline), her father quickly discovers him in her room and he has to take on his alterego - Hermionie Ayasaki - to keep from suffering his wrath, and becomes the family maid for the duration. Kotetsu (the family butler and male love interest) falls in love with the alter-ego, just like in the main storyline.
- In an episode of Cardcaptor Sakura, Kerberos (AKA: Kero-chan) and Yue (Yukito's true form that "Yukito" doesn't know about) are unable to return to their alternate forms because Eriol uses his magic as their creator to force them to stay in their true forms. Sakura struggles to address the problem that a large winged panther and a winged bishounen are hiding out in her bedroom.
- In A Certain Magical Index, Touma hides Index in his apartment, since she isn't an Academy City citizen and could be arrested or deported. She later becomes a citizen, ending the problem. The pair also hide their cat Sphynx, because the landlord doesn't allow pets.
- Parodied in Beelzebub, including the excuses denizens from Hell use to insinuate themselves into unsuspecting families.
- Fractale pulls a somewhat shorter version of this.
- In the last arc of Sound of the Sky, the crew hides a captured enemy soldier that they found trespassing on their border (for a harmless reason) to avoid messing the already troubled ongoing peace talks.
- Happens in several occasions in Fullmetal Alchemist. First when Knox accepts to treat and hide Lan Fan and May Chang after the former lost an arm and the latter escaped from the Homunculi. Later, Ed, Darius and Heinkel are sheltered for a while by shady doctors (for a price).
- During the course of Fate/Zero, Waver has to hide Rider in the room he's "borrowing" from two locals. Rider, for his part, does not make this easy.
- Outside of Decode, part of the premise of Birdy the Mighty involves Tsutomu trying to hide the fact that that's to the title character's recklessness, he's now sharing a body with an attractive female space cop—to varying degrees as in the original and remake manga as well as the OVA, his dad's attempt at Bathtub Bonding results in him seeing a naked Birdy and in the OVA, Birdy at one point takes some of Tsutomu's sister's clothes to wear.
- In Ultimate Spider-Man, Peter once had to hide Wolverine.
- A graphic novella called Good As Lily is about a teenaged girl who encounters three different versions of herself: as a kid, as a career woman, and as an old lady. She hides all of them in her bedroom as she tries to figure out what to do with them.
- The New God named Metron once crash landed on Earth and lost his memory. Because people in the DC Universe are apparently extremely jaded the random little kid who saves him doesn't seem more than slightly surprised.
- Green Lantern: Sodam Yat's backstory has him taking care of an alien that has crash-landed on his planet, which just so happens to be very xenophobic, and stigmatizes any form of space travel/exploration.
- The original (1960s) version of DC's Stanley and His Monster went in for this in a big way. In addition to the monster, who was hiding from the modern equivalents of a pitchforks-and-torches-wielding mob, Stanley also ended up hiding a leprechaun and a German dwarf who didn't want to have to deal with the US immigration service, and the ghost of Napoleon, who wasn't so much hiding as haunting a grandfather clock and hoping for some decent wine. The later revamp, drawn by Phil Foglio, had only the monster, who was now a nameless demon exiled from Hell for being too nice.
- In one short story The Punisher is found unconscious in a bayou swamp by a local woman, who tries to hide him from both the gangsters looking to kill him and her own abusive husband.
- In Welcome Back, Frank the Punisher ends up in this situation in his own apartment building. He collapses from multiple bullet wounds and is discovered by his neighbors, Joan the Mouse and Spacker Dave, who end up having to hide him from mobsters that come looking to finish the job.
- In Raymond Briggs' The Man, a boy must hide a tiny and very demanding man in his bedroom.
- In DC: The New Frontier, when black vigilante "John Henry" escapes from a lynch mob. Badly injured, he is discovered by a little white girl and pleads for her to help him. Tragically averted.
Little girl: Over here! The nigger's over here!
- In the 1994 Punisher multi-part storyline, Frank is too ill to understand that hiding in a little girl's treehouse to recover is a terrible idea, because so many people are out for his head. The little girl is mentally disabled so her father, the SHERIFF, doesn't quite catch on right away. Then the Sheriff has Frank beaten for trying to touch his daughter.
- Twilight Sparkle hides Chirp, a human, in her library in the My Little Pony: Friendship Is Magic fanfiction Silent Knight. At one point she buries him under a pile of books to hide him from a patron.
- In this humorous Jojos Bizarre Adventure fanfic, Josuke, Okuyasu, Koichi, and Mikitaka keep Kars, revived from a meteor that fell back to Earth in the Nijimura house's attic.
- In Pixar's Monsters, Inc., Sully and Mike are forced to keep a human child in their apartment and later take her to work with them. They end up having an argument over her in full view of their coworkers, and take the above-mentioned play excuse Up to Eleven by spontaneously breaking out in song. Their deception is made even harder by the fact that if the girl screams or laughs the circuits overload and fuses get blown.
- Inverted in Tangled. While Rapunzel briefly does keep Flynn hidden in a closet while Mother Gothel is around, she doesn't want to keep him a secret. She wants to use the fact that she knocked out and locked up an intruder as proof that she can handle going outside (It Makes Sense in Context). Mother Gothel refuses to listen and never finds out.
- Planet 51 is an inversion of E.T, with the plot being about a human astronaut landing in a world populated by aliens and hiding out with the help of a friendly resident alien.
- Aladdin did this with Iago in Aladdin: The Return of Jafar, although it was because he wanted to break Iago's HeelFace Turn gently to the Sultan and Jasmine.
- The Iron Giant:
- Briefly done when the eponymous Giant comes to see Hogarth in his house.
- Done again later when the Giant ends up staying with Dean... and the Army comes by.
- E.T. the Extra-Terrestrial has an entire family (or at least the younger set) hiding a friendly alien.
- The Fat Albert movie displays this trope strongly.
- The entire plot of the 1980s classic Hiding Out, starring Two and a Half Men's Jon Cryer as an accountant who has to go on the run from the mob, or some crooked police, or something.
- In the 2007 Transformers movie, Sam Witwicky is lucky his parents are clueless enough to not notice that what happened to their backyard had to have been done by someone really, really big, rather than being an earthquake.... Then again, they knew he was trying to hide something, they just thought it was the girlfriend that he'd brought up into his room.
- Utilized in The Transporter where Shu Qi's character, Lai, is introduced as "The new cook" (as opposed to "the maid") to the Police inspector who is surprised at the change in Frank's (Jason Statham's) normally routine, and deceptively mundane, lifestyle.
- In Good Bye, Lenin! a young man's mother falls into a coma in East Berlin; when she wakes up, the doctor tells him that even the smallest shock might send her into a coma again. However, while she was in a coma, the Berlin Wall fell, and the Communist East Germany she knew no longer exists. Thus, the reunification of Germany becomes the Batman in his basement, as he goes to increasingly desperate lengths to make her think East Germany is still as she remembers it.
- In the film Volver a woman who runs a hair salon out of her house has to keep her customers from finding out that her mother, who is supposed to be dead, is living with her. She convinces them that her mother is a Russian lady who speaks no Spanish in order to forestall any awkward questions. Whenever someone who would recognize her visits, the mother hides under the bed.
- The first Hellboy movie has a scene of the title character Roof Hopping, when suddenly he runs into a little boy who likes to sit up there with the pigeons. They hang out and eat cookies while Hellboy throws pebbles at a perceived romantic rival on a street below them. It's one of the best moments of the movie.
- In the 1997 Disney film Under Wraps, three kids hide a reanimated mummy in the main character's bedroom. This is where his obsession with horror film memorabilia comes in handy.
- In the Soviet classic Ivan Vasilievich Changes Profession, Shurik is an inventor whose Time Machine accidentally brings Ivan the Terrible to his apartment. He is forced to hide the tsar from his wife, nosy neighbors, and the police, while he fixes the damaged machine. The twist is the tsar is a dead ringer for one of his neighbors (who is stuck in the past, impersonating the tsar), so naturally everyone assumes it's him.
- In Gamera the Brave, a boy named Toru hides a baby turtle from his father. Little does he know, it is Gamera!
- Iron Man 3: Iron Man in my Garage. Notably, Tony's in and out over the course of, apparently, a single night. Also, "Tony Stark is in my van!" as said by a gigantic fan with a tattoo of him.
- Before Iron Man, Thor had Jane Foster, Dr. Selvig and Darcy hiding Thor in their car dealership-turned-astrophysics lab when he fell to Earth.
- In A Country Christmas, a powerless Santa must hide in a barnyard.
- In Prancer, the kids hide a live reindeer in their barn.
- In Milk Money, the kids hide a runaway hooker in their treehouse.
- In Tiger Bay, the Hooker with a Heart of Gold Christine hides fugitive Bronek in her apartment when the police come to look for him.
- In The Shape of Water, Elisa hides the Asset (an amphibious humanoid) in her bathroom after she and her friends rescue him from the government laboratory.
- In Hot Bot, Limus and Leonard try to to hide the advanced sexbot Bardot in Limus' house and keep her hidden from his family.
- The protagonist of Beachwalker spends most of the book hiding an escaped POW in a basement. It doesn't help that said refugee's enemies have control of most of the town.
- Chrestomanci: In The Lives of Christopher Chant, Christopher has to hide the Goddess when she escapes from being sacrificed to Asheth because she's no longer a child which would be easier if she wasn't a powerful sorceress, and if she hadn't brought a newborn orphaned kitten with her.
- The Dresden Files: In Turn Coat, Harry hides Warden Morgan, who is wanted by the White Council for the murder of a Senior member.
- In the first of The Executioner novels by Don Pendleton, the protagonist Mack Bolan is found by a "Marion the Librarian-type" after he has collapsed unconscious from his injuries following one of this raids on a Mafia target. She hides him in her house from both the police and the Mafia while she nurses him back to health and even launders his battle suit.
- Not in the basement, per se, but in Harry Potter and the Chamber of Secrets, Harry has to keep a very noisy Dobby hidden from his aunt and uncle during a dinner party.
- Omri has to conceal various tiny live people in his bedroom in The Indian in the Cupboard and its sequels. Hiding the tiny people is easy enough, getting them food isn't impossible, but when they start demanding coffee and whisky, neither of which are normal things for a nine-year-old to want...
- In Thomas Love Peacock's satirical novel Nightmare Abbey (1818), the hero finds himself having to conceal a beautiful woman he believes to be a political refugee caught up in a web of Illuminati conspiracies when she's actually just a fellow Upper-Class Twit on the run from the marriage her father has arranged to the hero himself. Their endless (thankfully offstage) conversations on Kantian philosophy don't make up for what happens when his girlfriend finds out. With a clear parody of the trope Older Than Radio, the trope itself is probably at least as old.
- In The Secret Sharer by Joseph Conrad, a ship's captain hides a stowaway in his cabin, concealing him from the rest of the crew.
- In a short story titled "Such a Sweet Little Girl", a Creepy Child has a ghost in her room. Played with in that the girl in no way makes the ghost's presence a secret (and in fact openly brags about it), but everyone in her family dismisses the signs anyway.
- This is the plot of the novel The Sugar Queen with a girl in the closet of the protagonist.
- In The Wish Giver, a girl must hide a traveling salesman she has a crush on, who is turning into a tree in her backyard after she wished that he'd "take root" in her town. During the time she tends to him, she learns that he's actually a pretty big jerk.
- Young Wizards: The main character's family in Wizard's Holiday and part of Wizards at War is perfectly aware of the alien exchange students living in the basement, but they have to keep their existence secret from everyone else in town.
- This is the basic plot of ALF, which is about a common family hiding an alien, and making lame excuses to avoid visitors from realizing that.
- Excellently done on Arrested Development. Michael guesses correctly that his son is hiding someone in the attic, but assumes it's his girlfriend rather than his fugitive grandfather on the run for "light treason". This leads to the following exchange when his son tries to confess:
George Michael: I have Pop Pop in the attic.
Michael: What? The mere fact that you call making love "pop-pop" tells me you're not ready!
- Inverted in Buffy the Vampire Slayer when Xander had to hide the villain Spike in his basement, to avoid his recapture by the Initiative. Also, in Season 7 he keeps Spike in his closet (which is huge).
- Doctor Who: In "Human Nature"/"The Family of Blood", the Tenth Doctor hides himself in this manner by storing his Time Lord memory and genetics in a locket and tricking himself into thinking he is an Edwardian-era boarding school teacher so that the Family of Blood will not track him down and kill him. His companion ends up posing as a beleaguered maid, retaining full knowledge of why her "employer" has good reason to act so out of character. Eventually, the Family finds him anyway, and we learn the real reason he did it: to save them from the Fate Worse than Death he has to unleash to stop them.
- Subverted in the Farscape episode "I, E.T." Crichton lands on a planet that's never encountered aliens, and is caught by a young boy. He assumes this is going to be an E.T. story, and is aghast when the boy almost immediately calls for his mom. Then the two argue about what to do, with the adult wanting to hide him and the child wanting to turn him in to the military.
- Frontier Circus: In "Karina", Casey and Tony hide the runaway Karina in Casey's wagon, initially keeping her presence secret from Ben.
- The first season of Harry And The Hendersons was about an ordinary suburban family attempting to conceal a bigfoot in their home.
- Hider in the House (no relation to the 1989 horror movie of the same name) was a children's gameshow that invoked this trope. Contestants would have to hide a celebrity in their house and keep it a secret from their parents, while also trying to complete challenges for prizes.
- This is the premise of Nickelodeon's sitcom The Journey of Allen Strange, about a brother and sister hiding a stranded teenage alien in their attic.
- Masked Rider: When Ferbus first arrived, Molly and Albee had to hide him due to Hal's allergies, but Hal is not allergic anymore around Ferbus; once he revealed himself, Ferbus was accepted as part of the family.
- This is the basic premise of Mork & Mindy. After Mork from Ork is sent to Earth, Mindy hides him in the attic. Played with in that Mork does go out in public, but tries (with Mindy's help) to keep is true identity (as an alien) a secret. This eventually changes when the get married in the 4th season premiere.note
- In The New Adventures of Beans Baxter episode "There's No Place Like Omsk", Beans hides a Russian defector, who happens to look exactly like Miss Universe Shawn Weatherly.
- Our Miss Brooks: In "The Jockey", Miss Brooks and Mrs. Davis hide a jockey and his racehorse in their garage until he can win a big race and pay his debts.
- An inversion in The Outer Limits (1995) episode "Resurrection", where two robots clone/birth a human after humanity goes extinct, and have to hide him from the other human-hating robots. The robots ultimately sacrifice themselves and shut off themselves and their brethren to give the Earth back to the new human race.
- Power Rangers Zeo: Bulk and Skull hide an amnesiac Goldar & Rito in their basement for a while.
- In Smallville, Eternal and a couple episodes after it, Chloe is forced to keep Doomsday in her basement, and disposes of the bodies, which is both terrifying and tear jerking.
- In the series Spellbinder, there were times when Riana was hiding Paul in her barn and then, when they went through to Paul's world, times when Paul hid Riana in his house.
- In the sequel series, Spellbinder 2: Land of the Dragon Lord, the young Dragon Lord was hidden from invading barbarians by a local family.
- Mike hides Eleven in his basement in Stranger Things, both because they would cut him up and because he thinks she can help them find Will.
- In Rose Guns Days Season 1, Claudia hides Leo and Rose in her house just above her restaurant, when Caleb and his mooks put a reward on their head. Since she left club Primavera before Amanda took it over she can slip under their radar. Until Amanda remembers about her.
- In Harvest December the hero invites the town goddess to live with his family after she's Brought Down to Normal.
- In Sluggy Freelance, after accidentally bringing a man-eating alien into our dimension, Torg ends up giving her a job as secretary to his web design business and letting her stay at his place. He doesn't have to put up much of a Masquerade, however, since everyone who might care about the alien in his apartment either already knows, or is gullible enough to mistake her for a lamp/party decoration/really ugly woman. Or eaten.
Torg : YOU ATE ANOTHER CLIENT!?!Aylee : I'm sorry!
- Misfile: Ash can't exactly hide Rumisiel and Vashiel in his room given the length of the comic's run. Instead he tells his father that Rumisiel's his boyfriend and Vashiel his brother who got kicked out of the family home.
- Used in Coming Up Violet when Dawn crosses the proverbial pound and is forced to stay with the eponymous character and her guardian's family. Violet then deflects attempts by her friends to go to her house while the still traumatized human girl stays there. Eventually, they make a disguise for her so that she can move about freely though.
- Trapped in Another World, which is (for several reasons) inhospitable to her, Emily from Astray3 finds shelter with a friendly local family. This ends in a disaster.
- The name of the trope comes from an episode of Batman: The Animated Series, in which a boy hid an injured Batman in his mother's basement. The kid's friend frankly tells the mother what they're doing, but she assumes he's playing with his friends.
- In American Dad!, Stan and his family hide Roger - an alien avoiding government capture - in their attic.
- Another Episode, AT: The Abusive Terrestrial, has Roger, after a short series of circumstances, starts living with another kid temporarily, similar to ET. However, the plot doesn't focus on the kid hiding him, rather on the fact the kid starts abusing Roger and Steve tries to get him to leave the little punk.
- The Simpsons: In separate episodes, Bart takes in Otto (kicked out of his apartment) and Chester Lampwick, a hobo who invented Itchy & Scratchy. He keeps them both in the basement, but his parents find out fairly quickly.
- Lisa: Mom, there's a funny smell and a lot of bad language coming from the basement, and dad's upstairs.
- In "The Fool Monty", Bart finds a brain-damaged Mr. Burns in the woods and takes him home, attempting to hide him in his bedroom.
- In an episode of Ultimate Spider-Man, Peter has to hide, of all people, the frickin' Hulk in his bedroom, in a situation similar to that of the Trope Namer. With the Hulk being the Hulk, he has a really hard time keeping Aunt May (who is right downstairs) from noticing.
- Anyone who's tried to take in a stray animal as a kid has been through this.
- All the brave people that sheltered Jews from the Nazis or runaway slaves through the Underground Railroad.
- In France, when Corsican nationalist Yvan Colona was sought for the murder of a prefect, several families hid him from the police, for several years. He has been arrested and convicted since then − although whether he really was the culprit remains unclear.
- In the late 1960s, anti-Vietnam War activist Daniel Berrigan was hidden for some months.