All over the world, reports are coming in of children disappearing in the dead of night en masse. Chibi-Usa has a chance encounter with a boy named Perle and gives him a bag of cookies as a gift. One night mysterious flute music begins drawing all of Juban's children for an unknown purpose including Chibi-Usa. The Sailor Guardians eventually locate the source of the music and learn that an evil queen named Badiane is abducting children for their dreams to create a world ending Black Dream Hole which the guardians must stop.
The final theatrical Sailor Moon film based off the original anime, the movie was produced during the run of Sailor Moon SuperS which adapted the Dream arc of the manga. The movie with its emphasis on dreams and Pied Piper of Hamlin by way of Hansel and Gretel narrative falls well in line with the established tone and aesthetic that characterized the arc run at the time. Fan reaction is pretty divided on SuperS because of its focus on the equally divisive Chibi-Usa, but I personally don't mind the arc. Admittedly the biggest drag on SuperS is the fact it's burdened with following in the steps of S that adapted arguably the strongest most "stakey" arc with the Death Busters, and following that very strong and often dark arc with an arc based around circus iconography and dreams was always going to pale in comparison. While Chibi-Usa was very grating in Sailor Moon R and her inclusion as Sailor Chibi-Moon in Sailor Moon S was often used as a running gag in how "stupid" the show seemed to think Sailor Chibi-Moon was as a concept. Sailor Moon SuperS for all you can criticize about it at least tried to build Chibi-Usa as a character which I personally felt was more successful than not (though your mileage may vary). Sailor Moon SuperS: The Movie on the other hand not only feels like an abridged version of many of the elements seen in the SuperS arc of the anime, but it's also lacking in an emotional core like Sailor Moon S: The Movie managed to establish, and feels like there's too much in too little time.
The movie "tries" to have an emotional core with Chibi-Usa striking up a relationship with Perle who seems to be a boy but is in fact a "candy fairy", and from the character design with wings and white clothes to even the purpose the character serves storywise, this is a pretty shameless repackage of the relationship between Chibi-Usa and Helios the Pegaus from the SuperS arc which regardless of how you feel about SuperS as a whole was better done by virtue of allowing enough time to develop the relationship between Helios and Chibi-Usa so it had the resonance it needed. The screentime between Chibi-Usa and Perle is 3 maybe 4 minutes (if that). I will say that the movie at least looks nice with the animation and design work being well done with the innards of the floating "Marzipan Castle" having some truly amazing sequences such as a very elaborate tunnel sequence. The villains however are pretty underwhelming with Badiane feeling like a reskin of Queen Beryl and the garish "candy themed" aesthetic of the Candy Fairies ships and Marzipan Castle feeling like leftover assets from the Dead Moon Circus.
Sailor Moon SuperS: The Movie is passable. Like the other Sailor Moon films, the movie exists with little regard to the series continuity serving as an excuse for slightly more polished animation than the TV series and telling a story that has no real lasting impact on the characters, story or setting. In terms of quality I'd probably say this is the second best of the Sailor Moon films nestled between Sailor Moon R at the bottom and Sailor Moon S at the top. We do get a complete story with a defined beginning, middle, and end, and on a technical level it's well animated, but the movie feels like it's a cliff note version of a season of the TV show that doesn't actually exist. It's serviceable enough for a quick "done in one" entry in the series, but it's not all that memorable.
