Special Vehicles Division 2 of the Tokyo Metropolitan Police are on standby and doing their usual business when the sirens sound; cue the Lock-and-Load Montage as they roll out to deal with a construction Labor rampaging through a suburb. The pilot is screaming for rescue, because his machine, which was recently upgraded to Shinohara Heavy Industries' new Hyper Operating System, is acting on its own and refusing to acknowledge his commands.
The team investigates and learns that the HOS's lead programmer, Eiichi Hoba, recently committed suicide by jumping off the top of an arcology being built in Tokyo Bay. As more reports of Labors running amok come in, the team realizes something has gone very, very wrong with HOS.
The film was followed in production order by Patlabor 2: The Movie in 1993, and in chronological order by WXIII: Patlabor The Movie 3 in 2002.
Patlabor: The Movie contains examples of the following tropes:
- Accidental Discovery: Asuma discovers what's wrong with HOS completely by accident when he finds a copy of the HOS master disc while digging through files at SHI's Labor factory and put it into their computer. He triggers the Computer Virus, which quickly spreads throughout the factory and causes everything to go haywire.
- Action Film, Quiet Drama Scene: The sequences of Detective Matsui tracing Eiichi Hoba's movements across Tokyo through old flophouses that are being demolished to make way for new construction.
- Arcology: The Babylon Project is a City on the Water that is being built in the middle of Tokyo Bay. At its center is the Ark, a self-sufficient Labor maintenance platform.
- An Arm and a Leg: The Type Zero loses an arm in the Ark's collapse, then it chops off one of Alphonse's while Noa is fighting it.
- As the Good Book Says...: Hoba left quotations from the Old Testament all over the place: the Babel virus is named after the story of the Tower of Babel from Genesis; he also leaves parts of Psalms for potential investigators to find.
- Back for the Finale: Kanuka Clancy went back to the NYPD between the OVA and this film, but she returns at the start of the third act to help Special Vehicles deal with the plot. This marks her final appearance in the OVA continuity.
- Big Good: Throughout the film, Captain Gotoh runs interference with the higher-ups and makes sure the Patlabor squad has the resources it needs to accomplish The Plan, even getting pontoon attachments for the Labor carriers from the JGSDF to convert the trucks into boats. He also tricks Asuma into going balls-to-the-wall on investigating Eiichi Hoba and HOS: he already shared some of Asuma's suspicions and knew his subordinate could figure things out in a shorter amount of time if he was motivated enough.
- Bittersweet Ending: The good news is, Everybody Lives and Tokyo is saved from being leveled by rampaging Labors. The bad news is, the team's efforts just mean they got the least terrible option in the Big Bad's Xanatos Gambit: the Babylon Project has been set back at least a decade (though it was still ultimately completed by the time of The Next Generation -Patlabor-). The bad guy still got what he wanted, and Shinohara's corner-cutting goes unpunished besides.
- Blue with Shock: Happens to the pilot of a virus-infected rogue construction Labor in the first movie when he realizes that the Second Section (and in particular, Ohta), which has a reputation for collateral damage, is here to rescue him. "I'M DEAD!!"
- Chekhov's Gun: Shige's landlady calls attention to the delivery of the morning paper. A few minutes later, that paper gives Shige an Oh, Crap! when he realizes Hoba plans to use an incoming typhoon to activate all the Labors in Tokyo Bay at once.
- Computer Virus: The Hyper Operating System contains self-replicating sabotage code that causes computer systems infected with it to go nuts—meaning a rampaging Killer Robot in the case of Labors.
- Cutting Corners: Hoba's plot would not have been possible had Shinohara Heavy Industries thought of having their new operating system code reviewed before pushing it to production, something that is standard procedure for any professional engineering firm. Reportedly they were a distant third place in the Labor industry and Mr. Shinohara got greedy about evening the odds with his competitors. As a result, HOS went to market containing a pack of encrypted files that nobody but Hoba knew the contents of.
- Destroy the Evidence: Planned by Gotoh the third act when he orders Division 2 to tear down the Ark based on the suspicions of Asuma, Noa, and Shige about the Labor incidents. He ships the HOS master disk that Asuma found to Shige's contacts at MIT in hopes they're able to prove that the HOS was responsible for the berserk Labors. But if they can't, all the evidence that Division 2 destroyed the Ark will be on the bottom of Tokyo Bay anyway, so they'll just play dumb and say that the typhoon that was going on at the time destroyed the Ark.
- Deus Exit Machina: Captain Nagumo and Division 1 are prevented from taking part in the Ark operation because they're in the process of switching over from their earlier-model Patlaborsnote to the Type Zero, which is compromised by the virus and therefore unusable.
- "Eureka!" Moment: Asuma realizes the Labors are being triggered by infrasound after Noa calls his attention to a dog barking at a sound nobody else can hear. He later figures out Hoba's plan is to use resonance between the Ark and Tokyo's buildings to make Labors go berserk across Tokyo after the whistling from a teakettle makes a glass cabinet door in Shige's apartment rattle.
- Gambit Roulette: The Big Bad's scheme is dependent on a typhoon passing by Tokyo Bay to set off the trigger condition for his virus across all of Tokyo, which does happen at the climax of the film. The problem is that he commits suicide believing that his plot has progressed past the point where it can be stopped over a week prior. Meteorological science is nowhere near good enough to predict the path of a typhoon that far in advance, so his plan coming to fruition before it was discovered and steps taken to thwart it beyond SV2's desperate effort to avert catastrophe was pure luck.
- Grievous Harm with a Body: During the battle on the Ark, Ohta is seen using a Labor's severed arm as a bludgeon, having apparently run out of ammunition.
- Harmless Freezing: After rescuing the pilot of the berserk construction Labor by ripping his cockpit out of the machine with Noa's help, Ohta puts the Labor down with gunshots to its coolant tank, and is promptly enveloped in ice. He suffers no long-term health consequences other than Sakaki carving him a new one for dumping his Labor in the river.
- Hero with Bad Publicity: Division 2 is regarded as a pack of reckless, trigger-happy idiots who cause massive collateral damage whenever they deploy: the pilot of the first rampaging Labor has an Oh, Crap! reaction when told his rescuers are from Div 2. This is mostly Ohta's fault, as he represents 50% of the pilots in the Division, and is a reckless, trigger-happy idiot.
- Hover Tank: The tank Labor in the Action Prologue is a ground-effect vehicle in addition to a Spider Tank. A JGSDF attack helicopter takes out this drive with missiles and forces it down so that the ground-pounders can ambush it.
- Karma Houdini: Shinohara Heavy Industries escapes any punishment for failing to notice that their new Labor OS had a virus embedded in it before installing it on every SHI Labor in Tokyo: the government allows them to cover it up since too many careers in the public and private sectors are on the line.
- Killer Robot: Labors that are upgraded to the Hyper Operating System have a tendency to go berserk.
- Law of Inverse Recoil: Hiromi test fires an anti-tank rifle at a mothballed patrol car, hitting it with enough force to not only blow the doors and wheels off but to blast the entire vehicle several feet into the air. Despite this, not only is Hiromi still alive after using it but healthy enough to participate in the climactic raid on the Ark facility.
- Manipulative Bastard: Captain Gotoh tricks Asuma into going balls-to-the-wall on investigating Eiichi Hoba and HOS: he already shared some of Asuma's suspicions and knew his subordinate could figure things out in a shorter amount of time if he was motivated enough. Asuma is pissed when he finds out that among other things Gotoh knew all along from Shige that the Patlabors were at no risk of going berserk and didn't pass that information along.
- Meaningful Name: The main villain Eiichi Hoba's name is a deliberate cipher of "Jehovah", which is acknowledged by Gotoh (as well as Asuma in a line unique to the English dub). The film as a whole has a lot of Biblical Motifs, with Hoba explicitly having a God Complex.
- More Dakka: In the opening credits, the JSDF hoses a HOS-infected Spider Tank Labor down with enough dakka to make an ork cream himself.
- Never Found the Body: Hoba jumped from the Ark into the ocean. In the climactic finale they pick up a signal from him in the building they're trying to demolish. Noa goes after him, but it turns out he really was dead: The employee badge with the tracker was attached to the leg of his pet raven.
- Nice Job Breaking It, Hero: With the team outnumbered by rampaging Labors during the assault on the Ark, Kanuka installs a clean Labor Operating System on the Type Zero and takes it out to try to improve their odds. Unfortunately, the HOS virus hung on in hidden memory and quickly reinfects the Type Zero, which ambushes Ohta.
- No OSHA Compliance: Notwithstanding the HOS Computer Virus, which was deliberate sabotage, the Spider Tank Labor in the Action Prologue is said to have been undergoing wind tunnel testing when it went berserk. While it would have been quite dangerous enough unarmed, it is shown to have been loaded with live ammunition it wouldn't have needed for such a test: it fires a chaingun at the JGSDF attack helicopters pursuing it, forcing them to take evasive action.
- Posthumous Villain Victory: Eiichi Hoba wanted the madness of the modern world reduced, and forced the team to choose between tearing down the Ark, or seeing half of Tokyo destroyed by rampaging Labors triggered by the typhoon, and then killed himself to ensure he couldn't be made to undo his work. They choose the former.
- Razor-Sharp Hand: The Type Zero's primary mode of attack is to straighten its fingers into a spearpoint and then rapidly extend the arm to stab opposing Labors. It's extremely destructive.
- Red Herring: The fears that Alphonse and Unit 2 might go berserk like the construction Labors come to nothing: it turns out Shige didn't believe the hype around HOS and never installed it on the Patrol Labors in the first place (he just changed out the boot-up splashscreen to make it look like he did).
- Rule of Symbolism: Enforced. The story as a whole has a lot of Biblical Motifs, with the villain being named after Jehovah and his plot inspired by the Tower of Babel narrative in the Book of Genesis, and the arcology targeted by Hoba being named the Ark. The economic redevelopment of the Tokyo Bay Area that underpins the plot is dubbed the Babylon Project, another major Old Testament name. Mamoru Oshii was inspired to add it all in based on Noa Izumi's given name sounding like Noah of the Ark.
- Sexposition: Subverted. Gotoh's Infodump about Ei'ichi Hoba's God Complex cuts back and forth between him talking and Captain Nagumo changing out of her uniform into civilian clothes in their office's closet, but we aren't actually shown anything titillating.
- Self-Destruct Mechanism: The Ark is built something like a flower, with a spiral of petals attached to a central column. These petals can be ejected with explosive bolts in an emergency, which SV2 uses to demolish the Ark during the climax. Additionally, there's a secondary manual fuse accessible from the Ark's crow's-nest that will blow all the bolts at once.
- Ship Tease: Asuma grabs Noa and half-forces her to go out for pizza with him to get her to talk to him about her worries about Alphonse. They went on to have a Relationship Upgrade by Patlabor 2: The Movie.
- Super Prototype: The AV-X0 "Type Zero" which was supposed to be an advanced replacement for the AV-98 Ingrams used by Division 2. It proved to be a fearsome opponent in melee combat against other labors, and when it was overtaken by the Babel virus it completely mopped the floor with Ohta's Ingram and Noa only barely managed to subdue it with a shotgun to the brain. Seeing as the Type Zero wasn't seen in the subsequent films (the AV-02 Valiant shows up instead), it can be assumed that the design was abandoned.
- The Teaser: The film opens with the scene of Eiichi Hoba's suicide, then the opening credits roll over the JSDF fighting a combat Labor through a forest, only for it to turn out to be unmanned once it's immobilized and opened up. Only then do we meet up with Special Vehicles.
- Tempting Fate: Sakaki and Asuma visit Shinohara Heavy Industries, his father's company. The head of production insists to Sakaki that the HOS is completely safe, only minutes before Asuma inserts a HOS master disk into their mainframe to look at the code and triggers the virus across their entire system.
- Thanatos Gambit:
- The movie starts off with the Big Bad jumping into the ocean. As a result, the police can't find out in time how his virus works.
- Additionally, Hoba attached his employee badge to his pet raven to set off a Never Found the Body paranoia, and give his pursuers a Secret Test of Character. Division 2 is only able to prevent the destuction of Tokyo because they decide to try and save Hoba when they think he's alive. They wouldn't have made it to the backup Self-Destruct Mechanism in time if they had decided to collapse the Ark with him still in it. This isn't explained outright, but Asuma implies the authorial intent when he remarks that "It pays to be cops who care about human life!"
- Tower of Babel: The villain's plot is explicitly likened to the story of the Tower of Babel in Genesis: Eiichi Hoba, whose name is a cipher of "Jehovah", thought that modern Japan had lost sight of its historical spirituality and is devaluing humanity in the pursuit of economic growth and advancement, and placed a Curse of Babel, i.e. the HOS virus, on Japan to restore the balance he believed was missing.
- Turn in Your Badge: Da Chief suspends Asuma for two weeks for a Long List of code violations he made during his investigation because he Didn't Think This Through—which Trickster Mentor Gotoh arranged so they'd have more time to figure out what's going wrong with the Labors.
- Xanatos Gambit:
- By killing himself, the Big Bad has left the police with only three choices to prevent Computer Virus-infected Labors from destroying Tokyo: Do nothing and let Tokyo's infrastructure get wrecked, destroy all Labors, or destroy the Ark thereby dooming the Babylon Project. Since the Big Bad is The Fundamentalist who feels that Ludd Was Right, all three options suit him.
- Captain Gotoh counters with a smaller-scale gambit of his own: he orders the team to demolish the Ark with its Self-Destruct Mechanism, and ships the HOS master disk to Shige's contacts at MIT to be analyzed. Assuming the team succeeds, one of two things will happen: either MIT is able to show that the HOS was responsible for the Labor rampages and prove that demolishing the Ark was necessary to save Tokyo, or they just blame it on the typhoon that was part of the Big Bad's plan because all the evidence they were responsible for the Ark's destruction will be on the bottom of Tokyo Bay anyway. Either way, Tokyo is saved.
- Zombie Apocalypse: The big battle in the first movie is a Hold the Line action to prevent civilization from being destroyed against an onslaught of slow moving, dumb, but relentless horde of opponents that are afflicted with a highly contagious virus that infects one of the good guys and turns it against his friends. Only instead of living dead humans, it affects construction mecha, the kind that were meant to easily demolish buildings and are used throughout the Tokyo Bay area.
