Released in 2008, Sigma Harmonics is a Square Enix RPG for the Nintendo DS, developed by the team that had previously worked on Dirge of Cerberus. It is set in an alternate Tokyo, and focuses on the story of Sigma Kurogami, the future head of the Kurogami clan, a line of 'sound-users' who can create miracles and guard the Great Clock that seals the demonic Ouma. The story begins when someone changes the past, destroying the present day and releasing the Ouma.
To put things right, Sigma and his friend, the card-user Neon Tsukiyumi, travel back into the past in order to solve a series of murders in the Kurogami household. By visiting different points in time, finding clues (in the form of 'moments of sound'), and working out the sequence of events and the culprit, the past can be changed, leading to a different murder scenario. In battles with the Ouma, Neon does most of the fighting, using her cards to perform actions whilst Sigma provides the BGM. By playing different tracks, the individual recharge rate for Neon's cards is changed. Neon can also change forms via a form of possession.
This game has an excellent soundtrack, composed by Masashi Hamauzu, and beautiful anime-style artwork. Sadly however, it has not yet been released outside of Japan.
Tropes associated with this game include:
- Black Eyes of Crazy: Rin during the final battle, coupled with Red Eyes, Take Warning.
- Boss Rush: Death Chapter, though each boss fight is also preceded by a simple deduction.
- The Butler Did It: Played With. The butler is the culprit in Chapter Three and a victim in Chapters Four and Five, and the maid, who is a victim in every other chapter, is the culprit in Chapter Four.
- Canon Welding: Neon appears in World of Final Fantasy as The Girl Who Forgot Her Name.
- Cool Mask: Worn by the butler.
- Determinator: The human race as a whole, given that they're willing to give fate the middle finger rather than lay down and die, and Sigma in particular.
- Dead Alternate Counterpart:
- In the original timeline, Yuu was killed in a car accident. Sigma comes from a timeline where that accident didn't occur.
- Sigma also encounters a timeline where Neon was the one who perished instead.
- "Do It Yourself" Theme Tune: Aya Hirano sings the theme song, "Harmonia vita".
- Evidence Scavenger Hunt: After going back to a certain time and a certain place, Sigma can use his sound-related powers to uncover 'moments of sound' - clues as to what happened in that place during that time.
- Everybody Did It: Also Played With. Every adult introduced in the various chapters ends up being a culprit in one of the murders.
- Fight Like a Card Player: The game's battle mechanics, explained in-game as Sigma playing music in order to control Neon's movements (since she has no conscious control over her body when being possessed by the guardian deities she summons for battle), along with a Rhythm Game like recharge mechanic.
- Gratuitous Latin: The theme song is named "Harmonia vita" and has some Latin sprinkled throughout the lyrics.
- Heroic Sacrifice:
- Neon sacrifices herself so that Sigma can travel in time.
- In another timeline, Neon died to save Yuu from an otherwise fatal car accident.
- Humongous Mecha: Used in the final battle.
- Identical Grandson: Mimiko looks exactly like her grandmother Neon.
- Impaled with Extreme Prejudice: Neon, at the end of the trailer.
- Living Lie Detector: Fuyou and Rin have this ability.
- The Not-Love Interest: Neon is set up as Sigma's apparent Childhood Sweetheart, they have some very flirty dialogue throughout the chapters, and after she sacrifices herself as part of the price one has to pay for time travel, Sigma decides to Screw Destiny so they can be together again... but it's heavily implied that they're blood siblings; Neon's difference in last name is due to her being adopted by the Tsukiyumi clan.
- One-Winged Angel: Rin in the final boss battle; this is a Square Enix game so it shouldn't really come as a surprise.
- Powers via Possession: Neon uses this to change classes. It also comes with a slight personality shift.
- Ripple-Effect-Proof Memory
- Say My Name: At the end of the trailer when Neon gets skewered.
- Screw Destiny: Humanity was originally doomed to be destroyed by Ouma. The Kurogami and Tsukiyomi households have been repeatedly going back in time to find a way to avoid this.
- Set Right What Once Went Wrong: Subverted Trope, as the Bad Future Sigma and Neon are trying to avert is what actually happened.
- Stock Footage: Whenever someone ends up being murdered, the freeze frame of their dead body being discovered is always the same no matter which timeline. This actually ends up being a clue to solve a mystery in Chapter 5, as the body Rin stumbles upon and calls "mother" uses the same freeze frame as Yuriko's murder in Chapter 3.
- Strong Family Resemblance: Yuu grows up to look identical to his father, except for hair color and the scar on his father's face.
- Synchronisation: Obaba turns out to be a pair of twins named Plum and Take who are so in tune with each other's sensations that only one of them can be awake at any given time. Fuyou uses this psychic connection to murder both of them in a way that gives her a convenient alibi.
- The Summation: After gathering evidence, Sigma can do this via Hyper-Inference (a board with the 'moments' placed on it in the form of medals, which can be placed in different ways, producing different inferences). Whether he infers rightly or wrongly affects the boss battle afterwards.
- Time Police: Played With. Sigma is indeed one, but the timeline he thinks he is restoring is the artificial future brought about by time travel. Rin is the Time Cop charged with returning things to the way they actually were.
- Time Travel: The plot of the game hinges on the conflict between at least two time travelers and their efforts to change the past.
- Timey-Wimey Ball: Time travel was originally presented as having a single timeline, with changes in the past affecting changes in the present. Then, The Reveal shows that multiple timelines are in play and the finale throws out pretty much every rule presented so far so that Sigma can essentially become a Reality Warper so that his timeline can exist instead of being erased.
- Theme Music Power-Up: What piece of music Sigma is playing affects the recharging rate for Neon's cards. Rin produces the opposite effect in the final battle by changing the track.
- Trust Password: Sigma uses one to get past the butler after the latter has "forgotten" him ( from the butler's point of view, this particular version of Sigma never existed) due to the changes in the timeline.
