Once Upon a Smile is a retelling of Smile Pretty Cure! by Cure_Shabon. Like other Pretty Cure fanfics of this franchise, it adds several new plot points, removes existing ones, and adds a Sixth Ranger to the main roster.
Once Upon a Smile contains examples of:
- Big Damn Heroes: Cygnet Drop during her first appearance.
- Evil Costume Switch: After becoming a servant of Queen Obie, Joker discards his canon white and purple outfit for a more regal look, almost looking like a vampire, and slicks back his hair.
- Evil Counterpart: The Bad En— pardon, Gemini Pretty Cures. Cygnet Drop also has one, hers simply named Odile.
- God Save Us from the Queen!: Queen Obie, ruler of the Nighterror Realm.
- Lower-Deck Episode: Yayoi is completely absent for most of episode 25 in this version. The episode that follows showcases her misadventures and first solo encounter with the Nighterror Realm at a superhero convention.
- The Man Behind the Man: Joker turns out to be this for both Pierrot and Queen Obie.
- Monster Mash: The Nighterror Realm characters.
- Frankenstein's Monster: Franken
- Our Vampires Are Different: Chii
- Villainous Harlequin / Monster Clown: Joker, of course.
- Youkai: Enenra
- Monster of the Week: After the Bad End Kingdom, and by extension, the Akanbes, meet their demise, Joker produces eyeball-shaped patches that allow Queen Obie's servants to create monsters known as Kusanics, which are considerably scarier in appearance than the Akanbes.
- Original Character: Hiyori, Nebbie, and pretty much all of the villains from episode 24 onwards (except for Joker).
- Shout-Out: The villain structure in this version seems to take a lot of cues from Super Sentai, particularly Tensou Sentai Goseiger with having more than one villain group and the reveal that Joker is the true Big Bad much like Buredoran/Brajira was.
- Sixth Ranger: Cygnet Drop
- Slipknot Ponytail: All six heroines have their hairstyles undone during the final battle with Joker.
- Verbal Tic: Aside from the canon characters, we have Nebbie's "-shigu" and Chii's "-de chi".
- Western Zodiac: The motif of the Great Stellar Demons.
