-->''"It's those weapons. Why in this day and age are you so set on using knives and katana?" ''
-->''"I'm not '''set''' on using them."''

Also known as ''Triangle Hearts Sweet Songs Forever'', [[SpellMyNameWithAnS depending on which piece of merchandise you're looking at.]]

The third entry in the ''TriangleHeart'' {{eroge}} series, which, like its predecessors, focuses on one boy and two girls trained in an ancient fighting style, the supernatural phenomenon surrounding them, and the threats that greed, lust and power present.

The titular triangle is formed by Kyouya Takamachi, only living heir to the Fuwaryuu sword style, and also practitioner of the Mikamiryuu style and has his own {{Harem}}, his "sister" Miyuki (actually his cousin), whose mother gave her to her brother and ran off to seek revenge against the man that killed her family, and Fiasse Crystela, an IdolSinger and long-lost childhood friend who has hurt her voice and is staying at their house.

Kyouya's father, Shirou, was killed by the same (supernatural) terrorist organization that once killed off the rest of his family, save for Kyouya, Miyuki and her mother, and now they set their sights upon the main trio. Kyouya has to stop them, as well as work out his friends' more-than-mundane problems. It also helps that they work for a clandestine special defense antiterrorist force forged from an alliance between China, Japan and the United States.

There is also a 4-episode [=OVA=] that takes place after the game. Fiasse is back on tour, but has received death threats, so naturally she calls upon the Takamachis. Her real bodyguard, Elise [=MacGaren=], absolutely refuses to let some amateurs she knew as a child take her place, and begrudgingly agrees to work with them, provided they stay on the sidelines. Elise uses a gun and insults Kyouya and Miyuki's insistence on the sword, despite quickly learning [[KatanasAreJustBetter how better off they are with katanas]]. But there's still something that she doesn't want to face, and seeing those two again is far too painful.

So who wins? Not Fiasse, not Miyuki, although Kyouya can pick either in the game -- it's Shinobu, the Japanese Vampire [[VictoriousChildhoodFriend Childhood Friend]]. [[DidntSeeThatComing Hm. Didn't expect that.]]

However, this series is probably best known for introducing Kyouya's adorable eight year old sister Nanoha Takamachi. Starting out as a satellite character with little relevance to the plot, she proved popular enough to be given her own MagicalGirl spinoff game, and then an anime... which eventually took off and [[Franchise/LyricalNanoha became an entire universe of its own]].

!!This game and OVA provide examples of:
* ActionMom: Mikami Misato.
* AllGirlsWantBadBoys: In the absence of Yuuno, Fate and Amy, Nanoha/Chrono is canon in this verse. And he's evil.
* AlternateContinuity: And one that's far better known than the game itself.
* AnalogyBackfire: Elise, arguing against allowing the "amateur" Kyouya and Miyuki to provide security for Fiasse, tries to tell Fiasse that professionals don't sing on the same stage as amateurs. Fiasse, a talented singer who does not see it as SeriousBusiness, says that anyone who likes to sing can do it together.
* AscendedExtra[=/=]BreakoutCharacter: Nanoha, of course.
* AudibleSharpness
* AxCrazy: Slicer from the OVA.
* {{Backstory}}
* BackToBackBadasses: Kyouya and Elise in the OVA opening.
* BadassFamily: The Takamachis.
* BattleButler: Noel, Elise, and Kyouya and Miyuki themselves.
* BewareTheNiceOnes: Nanoha; although her "befriending" isn't ''quite'' as violent as [[LyricalNanoha the one we know and love]], she still intimidates people twice her age despite her cuteness. Shinobu, too.
* BigFancyHouse
* BleachedUnderpants: The OVA.
* BloodKnight: Many of them. Utterly averted by Miyuki, though.
* BrotherSisterTeam
* CherryBlossoms: Nami, Nami, Nami, Nami, Nami. It helps that the trees are planted all over her shrine.
* ChineseGirl: Yung-fa from the original ''Toraha'' and new character Lian-fei.
* CloseCallHaircut: Miyuki's hair braids get sliced off when she ducks a sword swing.
* ContinuityNod: Two haremettes from the first two games appear as side characters.
* CreepyCoolCrosses: Slicer.
* DatingSim
* DefeatMeansFriendship: Nanoha's first-ever "befriending" -- she and Chrono hook up after she beats the tar out of him.
* DemotedToExtra: Virtually most characters in this game who carry over to ''Nanoha'' -- especially Kyouya -- suffer a steep decline in importance in the original series, and are virtually phased out in ''A's'' and ''[=StrikerS=]''.
** In-game example: Shinobu is the ''winning girl'', right? So why does she get so few scenes in the anime?
* DisappearedDad: Plenty of 'em, most prominent of which is Kyouya's father Shirou.
* DysfunctionJunction
* FailureKnight: Elise to Fiasse.
* FairyCompanion: Lindy to Nanoha in her mini-scenario in the fan box.
* FantasyKitchenSink: Ghosts, kitsune, Japanese Vampires, {{Magical Girl}}s, {{Robot Girl}}s, pixies, interdimensional invaders, and that's just this one game.
* ForgottenChildhoodFriend: Elise from the OVA.
* FullNameBasis: Elise addresses most characters this way, in Western naming order, at that.
* GratuitousEnglish: Quite a bit of it in the OVA, especially when an otherwise chilling conversation involving the main villain turns into {{Narm}} because of poor pronunciation and grammar. Also, Elise's "FREEZE!"
* HeirToTheDojo
* IdolSinger: Fiasse
* ImportantHaircut
* ImprobablyFemaleCast: Sort of. The school and town part are perfectly fine, but the special defense forces?
* [[OurVampiresAreDifferent Japanese Vampire]]: Shinobu.
* {{Joshikousei}}
* KillAllHumans: Kuon.
* KissingCousins: The Miyuki route.
* LastNameBasis: Kyouya and Shinobu, despite FirstNameBasis being fairly common among the cast.
* {{Meido}}: Noel.
** RobotMaid
** NinjaMaid
** By extension, [[NinjaPirateZombieRobot Robot Ninja Maid]].
* MartialPacifist: Miyuki, who states she can never get used to fighting, but fights to protect Fiasse.
* {{Miko}}: Nami.
* MoralityPet: Kuon gets a lot nicer from hanging around cute little Nanoha. Make [[DefeatMeansFriendship "befriending"]] jokes as you will; AlternateContinuity or not, it ''is'' Nanoha.
* MysteriousParent: Misato.
* NamesToRunAwayFromReallyFast: Slicer from the OVA.
* NoExportForYou: Hmm. {{Eroge}} are rarely licensed without the [[{{Bowdlerization}} David Bowdler treatment]], and those that are [[PornWithPlot usually don't have any plot]]. ''LyricalNanoha'' has had disappointing sales figures in the Anglosphere, and no press materials have even mentioned what it spun off from. The OVA can't be licensed on its own because it's a continuation, not an adaptation -- fansubbers even knew this, and had tons of screen notes detailing who everyone was and what the viewers who hadn't played the game were missing. Is it even ''possible'' to get this licensed?
** [[http://www.mangagamer.com/allages/ Mangagamer? (specifically the adults-only section)]]
* NotBloodSiblings: Miyuki and Kyouya are cousins who grew up together (even if she doesn't use JapaneseSiblingTerminology on him), but can end up in a relationship.
* PettingZooPeople: Kuon.
* PsychoForHire: Slicer [[RuleOfThree yet again]].
* RoadCone: The OVA, although it doesn't matter much, barely focusing on the Shinobu[=/=]Kyouya arc.
* RobotMaid: Noel.
* SchrodingersCat: Shirou is dead in ''Toraha'' but very much alive and retired in ''Nanoha''.
* SecretArt: The Fuwa-ryuu sword style, exclusive to the Takamachi family.
* SinkOrSwimFatherhood: Kaori, a woman Shiro had an affair with leaves Kyouya with him before leaving again, forcing him to raise Kyouya by himself.
* StalkerWithACrush: The Fan, Fiasse's terrorist stalker.
* ThirdPersonPerson: Shinobu refers to herself as "Shinobu-chan".
* TookALevelInBadass: Miyuki started training after Kyouya and Nanoha's father died.
* TwoGuysAndAGirl: Cheerful hero - Miyuki [despite being female], angsty hero - Kyouya, DistressedDamsel - Fiasse.
* UnluckyChildhoodFriend: Officially, Fiasse and Miyuki, although Miyuki's a cousin. Elise from the OVA is the strongest example, as she doesn't have a story path in the game and therefore can only ever lose.
* UnusualEars: Kuon.
* VictoriousChildhoodFriend: Shinobu officially, Fiasse and Miyuki if you pick their routes.
* VillainousCrossdresser: The Slicer infiltrates the concert disguised as a woman.
* WhodunnitToMe: Alisa.
* YouGottaHaveBlueHair: Akira, Chrono and Lindy; then there's Shinobu and Noel for purple, Sakura for pink, Lian-fei for green...
And now you know where Nanoha got it from.