Air Vent Passageway / Literature

• Somewhat altered in The 39 Clues: The Dead of Night, in which Phoenix Wizard and Reagan Holt try to escape the Vespers' prison by climbing up a dumbwaiter shaft. Justified, since the characters are children.
• Parodied in The Adventures of Samurai Cat, in which a cruise ship's air vents "... appear to have been designed for covert transportation." — "That would explain the moving walkways and vending machines."
• Used in Age of Fire, where the two dragon siblings escape from a raid on their home cave by escaping through naturally formed air passageways.
• Animorphs: The Animorphs use air vents like this from time to time but do so while in the forms of insects, which of course have no trouble with the space. Fans are more of a problem.
• Something similar to the above happens in Artemis Fowl: The Arctic Incident. Artemis has to crawl through a duct filled with fuel for the building's plasma weapons. Before his helmet runs out of air. Without being able to see where he's going. Knowing full well that if anyone turns on the plasma cannons, he's toast. Once he gets out, he has to be sprayed with anti-radiation foam or he'll likely develop cancer.
• The Ashtown Burials has Nolan showing Cyrus and Antigone how to travel via the underfloor heating ducts. It's pointed out that this is dangerous, especially in winter when the ducts may well be heated to burning point, but somewhat justified in that Nolan can't actually die. Acoustic License is averted, however, with Cyrus having to be told to shut up or anyone standing near a heating vent will be able to hear him. Later on, Nolan uses an air vent to trick Dr. Phoenix, by hiding in it and reading out old transcripts, though the vent and Nolan are both rather shot-up when Phoenix works out where the voice is coming from.
• Played with in the Blackcollar novel The Backlash Mission, where the air intakes for a huge underground military base are large enough an adult human can walk through them, in order to accommodate the massive inflow needed and the filtering equipment to keep out poison gas attacks. Since even with the vents camouflaged, this is an insanely large security risk, the intakes are designed with a very large kill zone of automated defenses, which are described as completely undefeatable and possibly viable for centuries without maintenance. They actually were completely undefeatable. But with the base abandoned, there was no one to stop someone from spending months tunneling around the killbox.
• Deconstructed in Black Dogs. The ventilation in question is portrayed as tough, claustrophobic going in the dark, with Lyra, the protagonist, suffering several minor injuries, and a high chance of her falling and breaking her neck. Or breaking something else that renders her unable to escape, and dying slowly over several days.
• In The Boy Who Knew Too Much by Roderic Jeffries, a youth breaks into an abandoned factory on a bet and finds himself pursued by masked thugs. The detective assigned to the case is reluctant to believe him, but then sees the marks where the kid dived down a chute and notes that he must have been pretty scared to have jumped in there without knowing where it came out.
• Cannon Fodder: Kelsey says she escaped from Black Jack's base in this way, but we never see it happen.
• Attempted by Rolas in Captive of the Red Vixen after he figures out that his Shock Collar is only tied to the door to his cell, but he finds a note from his captor and a trap waiting for him at the grille above the lifeboats.
• Subverted in A Certain Magical Index. In Volume 17, Touma asks if he could use the ventilation ducts in the plane, but the flight attendant says that the ducts are too small. Touma admits that wasn't the plan and asks for some hot tea and coffee to pour down the duct, causing thermal expansion and make the terrorist on the other side think that there's someone crawling through the ducts, who lampshades that the act is just as suicidal as coming in through the actual entrance he was training his gun on. As a result, the terrorist gets some boiling hot tea to the face when he shoots the ducts, which also distracts him from Touma barrelling through the door and flinging a full pot of boiling coffee into his face.
• Chronicles of Chaos: Used and lampshaded in Fugitives of Chaos when Vanity — who has the power to find-slash-create hidden passages — finds an accessible air vent.
• Ciaphas Cain:
  • In Cain's Last Stand, the air vents are exactly the place genestealers like to hide.
  • In other books, following a close call in Death or Glory, Cain makes a point of always acquiring the access codes to the maintenance conduits whenever he travels by ship. On one occasion where he didn't find the time to do so, Jurgen brought to his attention the fact that he was in a civilian ship, therefore its maintenance conduits didn't require access codes.
• Averted and lampshaded in Competitors, when Valentin and Lena are confined to quarters in a Space Station. When Valentin suggests escaping via the air vents, Lena laughs that he watches too many movies and points out that the vents are barely a foot wide. Valentin's suggestion to set off the fire alarm has Lena point out that this would cause the quarters to be depressurized to contain the fire.
• In Daystar and Shadow, a monkey crawls through a vent in the New Christians' stronghold to free Robin when he's tied up.
• The Disreputable History of Frankie Landau Banks features the steam tunnel and pranking variant, as it is set at a school similar to MIT/Caltech mentioned above. It should be noted that this does not occur without consequences: one character gets a moderately-to-severe burn from the exposed pipes.
• Played straight in a book based on the Donkey Kong Country series, Donkey Kong was trying to get to a room containing an auto defense system in a building being built by Kremlings. As he tries to think of a way to get to the 8th floor without being seen, he hears guards coming, and goes into a nearby ventilation shaft. It's big enough to crawl through, and even has signs pointing him in the right direction.
• Used in the last two books of the Dragonback series; the (less-than-subtle) justification is that large air vents are actually standard design in capital ships, so that in the event of a hull breach emergency air supplies can be funneled to the compromised areas in large amounts, buying the occupants time to reach emergency air masks and so on. Although humans can't fit through them as it is, so it can almost be called a lampshading. Shontine/K'da ships are actually designed for the stealthy, compressible K'da to be able to move through in case of hostile takeover, and a human sourly remarks that he outgrew the ability to navigate even big ships' navigation ducts when he was seven. When a K'da takes to those vents for the first time she gets thoroughly lost; in a later escapade she's almost caught when her tail twitches in shock enough to thump a vent.
• In the Dred Chronicles, the Prison Ship Perdition has enough of these that Tam, Dred's advisor, can use them to eavesdrop on rival gangs. This allows him to provide Dred with useful intelligence, which both protects the gang and encourages Dred to rely on him.
• James Bond escapes confinement in Dr. No through some ductwork, but he soon discovers that it was a purposefully-built series of hazardous obstacles (poisonous spiders, extreme heat, etc.), complete with viewports for entertainment, intended as a deliberate obstacle course set up by Dr. No.
• Duumvirate: The small kids who live in Northberg Educational Facility discover that they can go anywhere they want in the air vents. And the child-sized "secret" areas they lead to.
• Justified in Ender's Shadow. Bean uses the air ducts to explore and reconnoiter, but he can only do it because he designed a specialized workout to develop the muscles he needs to pull himself through at odd angles, and because he's really, ridiculously small. Eventually he grows too big to use the outflow vents anymore, but by then he is the commander of Rabbit Army and so has access to the larger inflow vents.
• Justified in Footfall, as the aliens are twice human size and deliberately put the captured humans to work cleaning the spacecraft's air ducts. Their prison cell also doesn't contain a handy air duct, forcing them to escape before using the ducts to evade.
• Used by Cammie and Macey in the third book of The Gallagher Girls series to get back into a building, though in this case it was still for escape rather than infiltration.
• Averted in Get Blank when Blank uses a false ceiling, rather than any kind of duct, to get around.
• In Going Postal, after a character fails to tunnel out of his jail cell, a guard remarks that the last guy in that cell — who happened to be unusually small and nimble — managed to squeeze through a tiny drain in the floor. Unfortunately, it didn't lead to the river like he thought.
  "He was really upset when we fished him out!"
• The 1958 sci-fi thriller Gold in the Sky by Alan E. Nourse explains why no one thinks of this trope until the protagonist Tom Hunter does. He has to sneak on board the orbit-ship of an asteroid mining corporation and rescue his friends (who don't think of using the vents until he stumbles into their midst), but guards are prowling the corridors. Some of the issues are addressed — the ventilation shafts are wide because it's a Starship Luxurious that needs larger ducts, Tom removes his boots to avoid noise, and is able to orient himself thanks to the direction of the Artificial Gravity plus he spends an hour roaming the ducts learning where everything is from the noises he hears through the grills. It's explained that once the Big Bad realises what's happening, he could easily flush them out by having his crew put on their spacesuits and then flood the vents with cyanide gas, so they use the vents to sabotage the ship, creating so much chaos that when the crew does realise what's happening they don't think of this easy solution; instead they try entering the vents, get disoriented because they haven't had time to get familiar with them, and end up shooting each other. Meanwhile the protagonists have taken the Big Bad hostage and use him to get off the ship.
• Slightly altered in Harry Potter and the Chamber of Secrets, using the castle sewer-pipes for the monster to invade from — and for the heroes to find — the title chamber. Hogwarts Castle has got to have the most gigantic pipes ever seen... particularly for being built by wizards. Somewhat justified, in that the pipe leading to the chamber was designed to be a passageway to it, and thus capable of being accessed by the Heir of Slytherin. Likewise, a massive snake would have much more success than other monsters in navigating plumbing. Both had been planned by one of the people who helped create the Castle in the first place.
• His Dark Materials: Lyra crawls around in the dropped ceiling in Bolvangar in Northern Lights. Being a twelve-year-old girl, she's smaller and lighter than most Action Heroes, but she gets caught anyway, and almost transformed into a soulless abomination. She's only saved because the Big Bad had a special interest in her, and was present.
• The main characters use this method of travel at one point in H.I.V.E.. The trope is played a bit more realistically than usual: the vents are not well-lit, the characters are concerned about the noise they're making, their route has some difficult paths and "obstacles", and there's some mention of the effect that crawling along a cramped space would have. When entering the vents, they have to use a screwdriver to remove the grille. The only reason they don't get lost is because of Otto's uncanny ability to remember their route. However, they oddly don't have any difficulty removing the exit grille (and due to the exit's location, there was no way they could have checked it beforehand). There's also no excuse for the lack of security cameras in the air vents, given they're big enough to crawl through.
• Used in the Honor Harrington spinoff Crown of Slaves, but used more realistically than many examples. Crawling around in them is murderously hard work, characters without detailed schematics get badly lost, and it proves almost impossible to remove a grille without the proper tools. Additionally, the ducts in question are on a space station and are deliberately designed to be large enough to crawl through since they double as maintenance access passages.
• In How To by Randall Munroe, the chapter "How to Build a Lava Moat" warns that you will need wide ventilation shafts, and the sort of person who wants a lava moat may find heroes crawling through them.
• In Illegal Aliens, abducted humans on an alien ship hide in the air vents, because all the movies say that's what you do in that situation — only they aren't air vents; they're conduits for a horrifically deadly gas weapon, which the aliens are preparing to flood throughout the ship, because they can't locate the humans....
• In the second book of The Immortals, Zek flees up a wall hanging and into an air vent to escape. He's a pygmy marmoset, a monkey about the size of a large rat and designed to climb well, so this isn't difficult for him.
• In short story "In the Bone", the protagonist uses air ducts which were too small for his alien opponent but nonetheless navigable by the smaller human form. Some of the ducts are indeed too small for the human.
• In the Iron Warriors novel Storm of Iron, this is how Hawke escapes a launching rocket and a Chaos Space Marine.
• Referenced in the Johnny Maxwell Trilogy book Only You Can Save Mankind:
  "I saw a film where there was an alien crawling around inside a spaceship's air ducts and it could come out wherever it liked," said Johnny reproachfully.
  "Doubtless it had a map," said the Captain.
• Golik from the Kadingir series uses the vents to infiltrate Zapp Castle and later to spy on La Résistance. He even mentions they are so convenient he'd better get rid of the air ducts in his own nightclub, lest someone tries spying on him.
• In the first sequel to Little Fuzzy, some would-be jewel thieves teach (and coerce) some "Fuzzies" (little furry aliens native to the colonial planet Zarathustra) into crawling through a ventilation system to steal some fabulously valuable gems. Justified in that an adult "Fuzzy" is only about two feet tall.
• Lucky Starr and the Oceans of Venus: Bigman volunteers to use an air vent in order to access a critical relay which, once disconnected, will prevent the Underwater City from drowning.
• Subverted in The Many Lives of Stephen Leeds. Ngozi proposes this as a way of getting into a building with security cameras — because she's seen it on TV — but J.C., who is a military expert (sort of), lists several reasons why it's impossible. They do find a creative use for an air vent, but it only involves hiding a mobile phone inside.
• Works better in Mrs. Frisby and the Rats of NIMH than in most stories due to the escapees being rats. Well, right up until the system starts ventilating. This is one of the scenes that, legend has it, convinced Disney to pass it by as an animated adaptation. Something about having a large part of the party wiped out faster than the Redshirt Army, and without even an enemy to credit for it. They need help in opening the grilles, too.
• Justified in The Occupation Saga. Jason pulls this off to outmaneuver Shil'vati opponents twice (once in a military training exercise, once while boarding an enemy ship). Shil'vati never see it coming because they're too big to fit through their own ventilation, whereas it's just a tight squeeze for Puny Earthling Jason.
• Subverted in One Fine Day in the Middle of the Night. After an earlier discussion of action movie tropes, one of the heroes spots the "Holy Grille" as the way out when they're held hostage. Unfortunately, he didn't reckon on the fact that crawling through metal ductwork is incredibly noisy, so everyone hears him as he tries to squeeze through.
• Paladin of Shadows: Both played straight and subverted in Choosers of the Slain. They need to sneak into the secure facility of one of the bad guys, so (played straight) they pick the slimmest girl on the team, as the men on the team are too large especially wearing all their weapons. Subverted because they knew she would get stuck half-way down when the air vents narrowed, so her sole job was to get to that point and release a small robot (an R2-D2 toy they had picked up in a toy store and then modified to include surveillance and communications gear) which could go the rest of the way.
• In Heaven's Queen, the third book of the Paradox Trilogy, when Brenton is helping Devi infiltrate Dark Star Station, he shows her a passage to crawl through and she assumes that it's an air vent. Brenton tells her that the people who built the station weren't that stupid; the passage is a power conduit, and usually filled with plasma heated to thousands of degrees. They're only able to use it as a passage because of a power outage.
• In the second book of the Parasitology series, Symbiont, Sally tries escaping captivity in a mall this way. She manages to make her way through the system only to find her guard Ronnie patiently waiting for her at the end; once he saw that she'd entered the vent, he was able to casually stroll over to the exit grating while she slowly crawled her way through the duct.
• In The Place Inside the Storm, Tara uses an air vent to travel from the psychologist's office to the room where Xel is being stored.
• Averted in Red Planet when one of the good guys proposes taking a vent grille off of a wall to get to the room on the other side. His friend points out that there will certainly be a similar grille on the other side, fastened by screws they won't be able to reach.
• The Sixty-Eight Rooms: The two kids manage to fit easily in the Museum's air vents as they have been shrunk down to five inches. Getting up to the vents was much harder.
• During the The Ship Who... Dissembled, two men are drugged, given no food, and locked into padded cells to keep them from coming to the aid of their brainship partners. Helva's partner promptly decides that there's no hope of escape and waits placidly for rescue. The other man, the Hero of Another Story, claws holds into the padding on the walls and with bleeding hands and feet struggles to the door at the top of the cell, gets through the vent set into it, and is found by the rescue party having crawled as far as the airlock.
• In the Spiral Arm novel In the Lion's Mouth, Bridget's first guess is such an escape before she deduces that in fact Ravn hid Invisibility Cloaks in the ventilation system, and then escaped, invisible, with her companion as soon as the door opened.
• Star Trek:
  • In the novel The Romulan Prize Riker, LaForge and a number of other officers escaped after being confined to quarters by the Romulans who took over the Enterprise using air vents. Unlike the larger Jeffries tubes and other service corridors the air vents are not meant for humanoids to crawl through, leading to Riker nearly getting stuck on several occasions.
  • Subverted and lampshaded in Star Trek: Section 31: Abyss. After escaping her cell, Ezri Dax goes up into an air vent, which (contrary to what the holonovels of her youth would have her believe) is very dirty, dark, small and has creepy things living in it. (She is, however, successful in using the air vents to move throughout the base to important rooms.)
• Subverted in the final book of the Sten series, by having the hero nearly get stuck in a claustrophobic moment.
• In Tales of Dunk and Egg, it's revealed at the end that Bloodraven had a few dwarfs sneak in through the privy to steal the dragon egg. Justified, seeing as they're dwarfs.
• In This Alien Shore, Justin shows Jamisia an air vent that leads to Mohammed's City, an area of the metroliner where non-Muslims aren't allowed. They spy on a marketplace.
• Time Machine Series: In The Rings of Saturn, the space pirate base has an extensive air ventilation system, extensive enough that a Mad Scientist was able to live alongside the inhabitants and move around the base for years without their knowledge.
• Under Alien Stars has a crew from a hostile alien race take over a hotel, placing their prisoners on one floor. They remember to seal the edges of the air vents, but don't know or don't care about the garbage chutes descending past each floor.
• In the Underdogs novel Acceleration, Ewan, Jack, and Kate are being pursued by clones on Grant's airship. They escape by knocking out a panel in a bathroom wall, sliding down a large pipe in the wall, and then crawling into a vent. They travel through the vent until they reach the room where 400 hypnosis victims are being held, which they break into by kicking out a grille.
• An Unkindness of Ghosts: Aster and Giselle run into the boiler room, climb up the pipes, and flee into the air duct to escape guards.
• Played with in The Vampire Files. Jack can justifiably play this straight if he assumes a gaseous form (gas, after all, being what air vents are designed to let through). However, he's a bit claustrophobic and can't shake the feeling of being trapped while traversing a ten-inch-square conduit.
• Comes up in several variations (breaking in, breaking out, air ducts, hanging ceilings...) in places in the Vorkosigan Saga, particularly the short story "Labyrinth" — where it involves problems like ducts forking or being blocked by grilles, and the others being only passable by the rather less than five-foot-tall main character, not his companions.
• In Wander, Wander and Dagger use the airvents to escape from a nest of smilers set up in an abandoned prison.
• Justified in Witch & Wizard. In order to free innocent children being persecuted by the government for being witches and wizards from prison, the protagonist Wisty infiltrates one of the prisons through the air vents..... but she turns herself into a mouse first.
• In the Women of the Otherworld short story "Chaotic" in the anthology Dates From Hell, Hope flees from a werewolf into an office, and finds herself in a dead end. She tries to escape through the air ducts, but she makes too much noise when moving and has to freeze when the werewolf enters the room. He finds her immediately. Later, after the pair has teamed up, they both move around through the air ducts, which are noisy, painful, cramped, and dusty. Still later, the bad guy enters a room looking for Hope, and while he's investigating the unscrewed air vent the good guys come out of their real hiding places and get the jump on him.
• The Zero Stone: In the sequel Uncharted Stars, while on the pirate space station Waystar, Murdoc Jern's companion Eet enters the station's air ducts to do some snooping.

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