[[caption-width-right:324:Box art of the Creator/DiscotekMedia release.]]

'''''The Secret of Mamo''''', or '''''The Mystery of Mamo''''', is the most common English name for the first animated feature film in the ''Franchise/LupinIII'' franchise, made in 1978 and originally released in Japan as simply ''Lupin III'' (''Rupan Sansei'').[[note]]The film is now known there as ''Rupan Sansei: Rupan tai Kurōn'' -- ''Lupin vs. the Clones'' -- in order to differentiate it from the four others that followed it.[[/note]] The animation style is based heavily on the original manga, rather than the cleaner appearances from the first ''Lupin'' TV series.

The movie has been licensed and released in the English-speaking world several times: First by Creator/StreamlinePictures in the early '90s, then Creator/MangaEntertainment did a UK release in the mid-'90s, then Pioneer[=/=]Creator/{{Geneon}} released it again in North America in 2003. The current license holder is Creator/DiscotekMedia, who put out their version of the film in 2013. The film is notable for being dubbed into English [[DuelingDubs four]] times (all collected on Discotek's release).

Lupin III has finally been hanged for his crimes, but eternal foe Inspector Zenigata isn't so sure. His instincts are rewarded when the corpse is booby-trapped by another, and very alive, Lupin III, expressing similar confusion at his own death. Deciding to take manners into his own hands, Lupin goes after the Philosopher's Stone, and sure enough draws the attention of perpetual FemmeFatale Fujiko and her mysterious benefactor. But when she steals the stone and it is revealed as a fake, things fall apart. Lupin and his gang barely survive a massive assassination attempt, and the eternally loyal Jigen and Goemon finally have enough and leave Lupin behind when he rescues Fujiko over their concerns.

Throw in [[{{Eagleland}} American secret agents]], a mysterious island with historical figures walking around, an ancient conspiracy, and several feats of what seem to be magic -- all revolving around Fujiko's contractor, a shriveled old man named Mamo. Can Lupin and his companions discover where the dead Lupin came from or what Mamo's plan is, or will they fall apart from the strain?

'''Complete spoilers below''' -- don't read further if you don't want to know how this caper turns out!

!!''Lupin III: The Mystery of Mamo'' provides examples of the following tropes:

* AmbiguousCloneEnding: Averted at the last minute -- Mamo eventually admits that the Lupin that died at the start of the film was a clone, and the protagonist was the real Lupin the Third. Lupin tries to invoke this at the end when Zenigata captures him, but the Inspector doesn't care.
* BigDamnMovie: Mamo is playing above the Lupin gang's usual weight class. [=ICBMs=] get involved. No, Goemon ''doesn't'' cut them.
* BrainInAJar: Mamo eventually reveals that his real self is a gigantic disembodied brain, that controlled his clone bodies by implanted microchips.
* BreakingTheFellowship: For a change, Fujiko's antics get Lupin to swear off her -- until she's found abandoned in the wilderness and TheDulcineaEffect kicks in. This is the last straw for both Goemon and Jigen, and the trio only barely avoids coming to blows before turning their backs on each other. (And, naturally, Fujiko's running the WoundedGazelleGambit for Mamo.) The gang regathers at Mamo's Caribbean island, but after Fujiko getting kidnapped and Goemon suffering a HeroicBSOD, Lupin is eventually forced to [[StormingTheCastle Storm the Castle]] alone, despite Jigen's attempts to talk him out of it (with bullets).
* CaptainObvious: "Ladies and gentlemen: The End."
* CassandraTruth: The Egyptian police initially don't believe Zenigata when he claims Lupin's broken into the pyramid to lift the Philosopher's Stone.
* ChainedHeat: At the end, Zenigata handcuffs himself to Lupin -- just in time for the duo to outrun a MacrossMissileMassacre over the credits.
* ChasedOffIntoTheSunset: The ending to this film provides a twist, by having Zenigata handcuff Lupin, then having them ''both'' run off together, being chased by missiles launched by the US and Russia.
* ChekhovsGun: The tip of Goemon's Zantetsuken, which breaks off about halfway through the film.
* CloneDegeneration: Mamo admits that he's suffering from this.
* CloningBlues: The question about whether the dead Lupin in the opening scene was a clone or not. Also, Mamo is a giant brain using a series of clones of himself to interact with the world. [[CloneDegeneration The clones are beginning to decay more quickly because of the original materials decaying]]; he wanted the Stone and the other items Lupin stole as ways to counteract the decay.
* ContinuityNod: Lupin mentions a levitation trick from the TV series.
* DependingOnTheWriter: Whether Zenigata wants Lupin dead or alive in this movie is up to who's translating. The Creator/{{Toho}} dub's Zenigata could very well be the most extremist portrayal by an English dubbing company for the film.
* DisneyDeath: Lupin in the opening scene.
* TheDragon: Frenchy
* DubNameChange
** The Toho dub changes some of the character's names (surprisingly, since this dub was produced by a ''japanese'' company). Lupin and Mamo's names are untouched, but Jigen is renamed "Dan Dunn", Fujiko is "Margot", Goemon is simply called "Samurai", and Inspector Zenigata is renamed "Detective Ed Scott".
** The Manga UK dub changes Lupin's name to "Wolf III" for copyright reasons.
* {{Eagleland}}: The villainous variation, with CIA agent Gordon kidnapping Jigen and Goemon so a Kissinger {{Expy}} can use them to find Lupin and Mamo. The pair has a habit of carpet-bombing Mamo's hideouts regardless of who's in the area.
* {{Fanservice}}: The first time we see Fujiko in this movie, she's taking a shower... and absolutely averting BarbieDollAnatomy.
* FlatEarthAtheist: Lupin. Justified, as he's able to accurately predict Mamo's constant parlor tricks the minute he sets foot on transparent glass.
* AGodAmI: Mamo thinks of himself this way, and he goes to a lot of trouble to convince Lupin and his friends.
* GodTest: After Lupin [[DoingInTheWizard Does in the Wizard]] of the psychedelic vision Mamo showed him in Colombia, he rhetorically challenges Mamo to prove that he's a god by doing something like causing earthquakes instead of "parlor tricks". The response is enough explosives set off to measure on the Richter scale.
* GottaGetYourHeadTogether: Flinch, after Goemon slices him. Unlike most cases, his head is literally coming apart.
* HypocriticalHumor: In the Toho dub, Fujik-- err, [[DubNameChange Margot]] when Lupin steals her car.
-->'''Margot:''' Stop, thief!
* InvisiblePresident: Lupin and Jigen find themselves communicating with him over the radio after getting nabbed by the CIA. In the Geneon dub, he sounds distinctly like GeorgeWBush (who, after getting fed up with the two thieves, calls them "terrorists" and "Democrats"). Jigen [[ITakeOffenseToThatLastOne isn't happy about the latter]].
* KillItWithFire: Lupin deals with Mamo in this fashion at the climax, incinerating him with his own lasers by reflecting them at him with the broken tip of Zantetsuken.
* LeaveNoWitnesses: At the end, while Gordon is having a wargasm over bombing anyone who knows of Mamo out of existence, not-Kissinger is making a call to have everyone else with him killed -- yes, including Gordon.
* MindScrew: Mamo arranges several of these for Lupin.
* ObligatorySwearing: The Geneon dub has this. Notable with the usually silent Flinch, who swears twice where he didn't even speak in the original.
* {{Ondo}}: The international version of the DVD unfortunately replaces the Ondo song written explicitly for this film with an extended version of the Lupin theme. The Toho dub replaces it with "Superhero", an incidental piece from the series, but the Streamline dub retains it.
* {{Ragequit}}: Inspector Zenigata goes rogue just so he can continue chasing Lupin even after things complicate his police department's case against the latter. [[FridgeBrilliance Such complications may be why he joined up with Interpol in the first place.]]
* SingleStrokeBattle: Goemon's battle with Flinch; after chipping Zantetsuken on {{The Dragon}}'s armored vest, they exchange another strike. The tip of Goemon's sword falls off -- and then the screen splits in three pieces that slide apart, corresponding to the three pieces of Flinch's head that he tries and fails to hold together.
* SpellMyNameWithAnS: Mam'''eaux'''/Mam'''o'''; Frenchy/Flinch/Flintstone; Starky/Stuckey.
* ThoseWackyNazis: Hitler is among the clones Lupin encounters. [[SugarWiki/FunnyMoments Upon walking into him, Lupin gives him the appropriate greeting.]]
-->'''Lupin:''' [original Japanese] Heil Hitler!\\
'''Lupin:''' [Toho dub] Heil Hitler!\\
'''Lupin:''' [Streamline dub] Heil, mein Führer!\\
'''Lupin:''' [Manga UK dub] Heil Schicklgruber!\\
'''Lupin:''' [Geneon dub] Heil, mein Führer!
* TheVillainKnowsWhereYouLive: Mamo skips the threat and simply has Frenchy hit the gang's hideout with napalm to show them that he really means business when he sends hitmen after them for giving him a phony Philosopher's Stone.
* VillainousBSOD: The Mamo clone Lupin intercepts undergoes this in his last moments as he goes on about how clones degenerate over time. The not-original Mamo subverts this when he realizes the Philosopher's Stone doesn't help much, if at all. When Fujiko asks if eternal life is just a dream, he responds that there's another way and takes Fujiko to a launching pad to explain plan B - trigger World War III with his private ICBM arsenal so he and Fujiko will become a new Adam and Eve.
* VillainousBreakdown: When Mamo receives a HumiliationConga at the climax. First his attempts at immortality go awry, then the government tracks him to his hideout ([[XanatosBackfire because he couldn't pass up a challenge from Lupin to perform a miracle]]), and then Lupin foils his attempt at bringing about the end of the world. That's enough for him to go bat-shit crazy and take Fujiko for himself, trying to roast Lupin with lasers whenever he tried to get near. He even sounds crazy yet truthful when he reveals that Lupin's death at the gallows had indeed been staged all along.
* WhatTheHellHero: Lupin gets quite a bit of flack from his own associates for associating with Fujiko.
* WhoWantsToLiveForever: This is Lupin's immediate reaction to Mamo's offer of eternal life and youth. Fujiko's motivation is to have both Lupin and herself immortal; when it becomes clear that Mamo's not interested in making Lupin immortal, she loses interest. As she puts it, [[AwLookTheyReallyDoLoveEachOther she doesn't want to live forever just to see Lupin grow old]].
* WreckedWeapon
** Goemon's face-off against Flinch leads to the tip of his Zantetsuken breaking off, which puts Goemon in shame, as he believes that he's unworthy to use the sword if it breaks even a little. That chipped-off tip later becomes the ChekhovsGun when Lupin receives it from Jigen.
** Lupin later destroys Mamo's missiles to leave Mamo completely helpless.
* XanatosBackfire: Mamo is killed by lasers he was trying to use in his last attempt on Lupin's life.
* YouMonster: Jigen describes Mamo as a monster, and Lupin echoes such sentiments to the original Mamo, a gigantic brain, at the climax.
* YourMom: Lupin pulls one on Goemon in the Streamline dub after the latter remarks that "the road to hell is paved with pretty women".