Futari wa Pretty Cure Flash Fire

Everything About Fiction You Never Wanted to Know.

One of many OC fics for the Pretty Cure franchise that have sprung up around Livejournal, this one is written by flamingruby and features a "fire and ice" theme.

An extradimensional paradise known as the Crystal Plains housed numerous wonders. Among them was the music's ability to sometimes take on the form of a note-shaped gem if a song is important. A full set is required to complete the melody. Note gems that followed the order of the rainbow were said to be special, magical even. One paricular set, the Rainbow Notes of Life, protected this world and was guarded by twin pegasi: Hinote and his sister Kouri.

Beings from the Black Realm invaded the Plains; their leader, Lady Dischord led them in an attempt to steal and destroy the Rainbow Notes of Life, hoping to corrupt the Crystal Plains into a place filled with noise, evil, and despair. A desperate Hinote and Kouri took the Rainbow Notes of Life, carrying them to a place they hoped would be safe: the Green Plains, better known as Earth.

Of course, Lady Dischord isn't deterred, and she and her minions continue their search, hoping to corrupt both worlds. Unfortunately, she didn't count on Hinote and Kouri awakening the warriors Pretty Cure, Ember and Glacier, alias Homura Boukeno and Yuki Hanshou. Starting from Episode 9, the initial duo is joined by a Third Ranger in the form Homura's friend Aiden, who works in conjunction with the pegasus Eika.

Together, can they find the eight Rainbow Notes and unleash their song to save both the Crystal Plains and the Green Plains?

A character sheet can be found here.

Tropes used in Futari wa Pretty Cure Flash Fire include:

Homura: (sighs) Please don't make me sing...
[later]
Hikari: Okay, sing the doll's part for me.
Homura: (shakily and badly) Star light, star bright, first star I see tonight. I wish I may, I wish I might, have the wish, I wish tonight...
Hinote: (covers ears) Now I remember why you don't sing, hino.