Needs a Better Title - the existing one is Dog Latin modeled after "dramatis persone").A song or piece of music that exists In-Universe and plays just as much a role in the story as the characters or events - the plot doesn't have to be about the music, but the story would be very different without it. Music used in this fashion tends to have some sort of personal significance to one or more characters. It tends to be introduced as a background element at an earlier point and is brought forward later at a moment of emotional climax. Applications vary widely: from the mundane, such as a link to an important event or memory, or an instance of Music for Courage, to something approaching The Power of Love in musical form, with ability to turn the tide in an "I Know You're in There Somewhere" Fight or inspire a character to great heights. It is not The Power of Rock, however, in which the music has actual supernatural power. Compare with Theme Music Power-Up.
- The eponymous Mr Hollands Opus. Mr. Holland tries to write his Magnum Opus but his "temporary" job as a music teacher gets in the way. But his teaching inspires thirty years worth of students, whom by the end of the film, come together for him to play the finished piece.
- In Close Encounters of the Third Kind, The Greys teach their abductees a five-note song, which becomes the chorus of "the conversation" - and the central Leitmotif of the soundtrack.
What are we saying to each other?It seems they're trying to teach us a basic tonal vocabulary. It's the first day of school, fellas.
- In Music and Lyrics, there are a number of in-Universe songs that play a role in the plot, most notably:
- Halley's Fourth and Fifths concerto from Atlas Shrugged fills this role: Dangy, whose favourite piece of music is Halley's Fourth, hears it in her head at pivotal moments of triumph such as the opening of the John Galt rail line. Meahwhile, she overheard a train conductor actually Galt working incognito whistling a song he identified as Halley's Fifth concerto...a piece which the rest of the world knew he had never finished before he disappeared. The search for Halley's Fifth is one of the clues that eventually leads her to Galt himself.
- Discworld's Night Watch: "All the little angels"", the soldier's song sang by the Watchmen who fought and died in its Glourious Revolution of Treacle Mine Road 30 years prior to the main timeline. Sam Vimes, having been thrown back into an alternate timeline, has already lived through the events: the song first appears in his memories as a portent of doom. But this is an alternate history and it has Sam Vimes in it... it does turn out different, but not exactly better.
- The flute music in "The Inner Light" episode of Star Trek: The Next Generation, popularly cited as one of the series best episodes: Picard is mentally transported by an alien probe into the memory-recreation of an extinct race of Human Aliens, and lives out a whole alternate life where he grows old and has children and grandchildren (a path closed to him in his real career). His alternate self learns to play a flute and composes a song for his daughter's naming ceremony which is also the Leftmotif of the episode. When Picard comes back to reality, the probe is opened and the flute is found inside: the episode ends with him alone in his quarters playing the song.
- "Althena's Song" in Lunar: The Silver Star and its remakes. Alex and Luna were originally going to play/sing it together at Burg's festival. It's the key to getting through to Luna in the form of a Brainwashed and Crazy Goddess Althena, so that Alex can get close enough to save her.
- In the expended story of Lunar: Silver Star Story Complete, after Luna has been kidnapped by the Magic Emperor, Alex and the party arrive at the lake of the Blue Dragon shrine. To reveal it, a couple in love must stand on the pier and sing together. After the other party member's failed attempts, Alex stands on the pier alone and plays the song - even though Luna's imprisoned some hundred miles away, she "hears" the song and starts singing with him....joined slowly by the other young girls imprisoned with her. The result is having the shrine revealed, but also a very moving scene.
Hello, Unknown Troper. You'll need to get known to lend a hand here.