"I just got in contact with the animal shelter, and they'll take them in."
"You could have told us that before, you silly twit."
-Serena and Raye
Serena has nightmares where she is unable to transform, due to the silver crystal fading. She tells Darien, who takes her to a house full of kittens to cheer her up. A girl is looking after them, and says that the cats' home is going to be torn down, so Serena and Darien offer to help her take care of them and find homes for them.
Kaorinite implants the Daimon pod in the girl's puzzle, as the girl is Kaorinite's next target, transforming the puzzle into a Daimon Heart Snatcher named Nekonnell. Nekonnell attacks the girl, but is attacked by the kittens. She fights them off and begins extracting the girl's Pure Heart. Amy, Raye, Lita, and Mina transform into Sailor Mercury, Sailor Mars, Sailor Jupiter, and Sailor Venus and fight Nekonnell. Sailor Jupiter uses Sparkling Wide Pressure (a variation of Jupiter Thunderclap Zap) and Sailor Mars uses Mars Celestial Fire Surround, but Nekonnell blocks with her tail, beats up Serena (who is unable to transform), and extracts the girl's Pure Heart.
The two shadowy figures (who destroyed Mikusi) attack Nekonnell and return the Pure Heart to the girl, seeing as it is not one of the three crystals. Then they leave, as they are only interested in getting the crystals rather than defeating the enemy. Nekonnell regenerates, as she appears to be made of puzzle pieces, and strangles Serena with her tail. Tuxedo Mask arrives and fights Nekonnell, but is at a disadvantage. Then when all seemed lost, the power of the love between Serena and Darien (which damages Nekonnell as she tries to attack them) takes them to the Moon Kingdom, where Sailor Moon receives the legendary Spiral Heart Moon Scepter. Sailor Moon uses her new finishing move, Moon Spiral Heart Attack, to destroy Nekonnell, restoring the puzzle.
Afterwards, Serena contacts the animal shelter, which takes all the kittens in.