Chibiusa and Usagi henshin and fight the monster who turns into a cat and runs off. Chibiusa is hurt lightly on the arm during the battle, but the strange girl lays on hands and heals the cut. Everyone is amazed and the girl admits that it's strange, but that she's had the power since she was a child. (There is a brief scene here where Uranus and Neptune appear, with Uranus dressed like Tuxedo Kamen, tee hee). Chibiusa asks for the girl's name before she leaves and the girl identifies herself as Tomoe Hotaru. Chibiusa is going to be seeing a lot of her in the next few acts.
Later, Usagi scolds Chibiusa for giving their identities away so easily. Chibiusa says that she wanted to be friends with the girl and that's why she introduced them so easily. She admires Hotaru's pale skin and Mamoru tells her that it's the color of plaster of paris. How beautiful! Perhaps he meant Alabaster X3.
Chibiusa doesn't show up again for a while, but when she does it's at the Crown and she announces to the assembled that she has been elected president of the fifth grade. That puts her at roughly physical age ten, and since she's still in the same class as Momoko and Kyusuke, that means she was nine in the previous story. Go powers of deductive reasoning!
The next time Chibiusa shows it's when the pictures from the amusement park are developed. They're great, although Momo-chan points out that Chibiusa left in the middle of their fun. Chibiusa wonders how Hotaru is doing and then later at home she looks at the handkerchief that Hotaru gave her while healing her arm. Ikuko-mama has washed it, but the blood still hasn't come out. Chibiusa wants to see Hotaru again so she gets a new fresh handkerchief and goes to the district where the labs are. Hotaru sees her and is surprised that she came all the way there just to give her a new handkerchief. She says that her father and his secretary Kaoli are in the labs, so she decides to invite Chibiusa into the house.
Chibiusa admires Hotaru's room because it's romantic. It's very dim, lit only by lamps. Hotaru says she likes the dark. Chibiusa asks if Hotaru also likes to dress in black, since she's just changed into black tights. Hotaru says she's trying to cover scars from an accident long ago. Chibiusa then asks what Hotaru's father is researching, since she lives in a lab, but Hotaru collapses and begs Chibiusa to fetch her amulet from the table. Chibiusa offers her own ginzuishou instead and Hotaru recovers. She tells Chibiusa that she thinks the monster that Chibimoon fought escaped from her father's lab because he does gruesome research. She asks Chibiusa to promise not to tell because her father isn't evil, he's just . . . eccentric. Yeah, that's one way of putting it. Chibiusa leaves to go home and Haruka picks her up in her helicopter. Haruka, Michiru, and Chibiusa have a short conversation about talismans and amulets and then they drop her off in her yard. Haruka and Michiru tool around in those helicopters a lot. Wow, their gas bill must be high.
The next day, Mamo-chan takes Chibiusa to Michiru's concert at the Mugen Dome. She is startled to realize that the world famous violinist is the same woman from the helicopter. Eventually the concert turns into an altercation where Chibimoon and Tuxedo Kamen are saved just barely from a daimon by the intervention of Sailor Neptune. Chibimoon notices Neptune's mirror and figures out that Neptune is Michiru.
Later, after the fight and during a senshi meeting, Chibiusa throws in her two cents and declares that she doesn't think Haruka and Michiru want to fight them.
A few days later Chibiusa comes by the Crown looking for Mamoru. Makoto says that if her classmates hear her calling for 'Mamo-chan' everywhere they'll think she's a baby even if she's the president. Chibiusa explains that she just thought he'd be able to help her with her homework. This homework consists of a little lump of clay that she's trying to mold into the shape of a holy chalice that her mother carried around. She hasn't been very successful yet, but she's still trying.
The other girls ask if the chalice was a weapon, but Chibiusa doesn't know. She does admit to sneaking into her mom's room a lot and lying on the bed and admiring things, though. She gets a little teary. Makoto asks her if she'd like to go home, but Chibiusa declares that she promised her mama that she wouldn't come home until she was an amazing soldier. She leaves to see if she can find Mamoru at home.
She finds Usagi and Mamoru at his house staring kind of tersely at each other. She asks if they've been fighting and if Usagi has been cheating on him. Smooth, girlfriend. They deny both counts and then Chibiusa asks if they'll help her do her homework: molding the holy grail. They agree and Mamoru looks it up in the encyclopedia (I love Sailormoon XD It's actually in the encyclopedia XD). They make it together with some stones and beads from the craft store. In fact, Chibiusa has fallen asleep by the time that they finish. Usagi and Mamoru kiss and make up and Chibiusa and Diana are pleased because they've really just been playing possum. So cute.
Some time later, the projects are handed back in class and the teacher gives them a new assignment: to give the thing that they made to someone they love to show gratitude. Momo decides to give hers to her mother for her birthday. Kyusuke gives his to Chibiusa and blushes a lot and claims that it's to make up for the fact that he's been a bad friend. Chibiusa decides to give her grail to Hotaru as a present and Momo-chan and Kyusuke are both jealous.
When Chibiusa gets home she tells Usagi that she's going to see Hotaru. Usagi is now aware that Hotaru's papa is probably up to something bad so she tells Chibiusa she's going to go with her to visit, ostensibly because it's dark and rainy.
At the lab, Chibiusa can't find the intercom so she barges right on in. Kaoli is about to eject them as trespassers, but Hotaru tells her that they're her guests. Chibiusa gives the grail to Hotaru and Usagi is somewhat astonished since the three of them worked so hard on it such a short time before. Chibiusa explains that the teacher told her to give it to someone important, but Hotaru says she doesn't deserve it and tells Chibiusa that she should keep it herself. Usagi is creeped out by Hotaru's immense eyes and and excuses herself to the bathroom.
Hotaru collapses into another fit as soon as Usagi is gone and confesses that she's been having them more and more frequently and she feels like someone else is talking in her head. Only Chibiusa's special amulet can help her, and Chibiusa tells her that it's the ginzuishou. Hotaru feels a presence inside her long for the ginzuishou and she is disturbed. Meanwhile Professor Tomoe catches Usagi snooping out in the hallway and escorts her back to Hotaru's room. He tells Hotaru its time for her checkup and Usagi and Chibiusa excuse themselves.
On the way home, Chibiusa sees someone who looks remarkably like Pluto in a crowd. She chases after her, but the mystery lady is gone before she can catch her. Shortly thereafter nasty plants threaten everyone and Usagi and Chibiusa head to Mugen Gakuen Botanical Garden to check it out.
They henshin to fight at the garden and Chibimoon desperately wishes there was some way for her to use her power. She hasn't had a weapon since the Mirai no Cutie Moon Rod was destroyed in the fight with the Death Phantom. As if someone hears her, Luna P falls from the sky and poofs into the Pink Moon Stick in front of her and she uses Pink Sugar Heart Attack for the first time. Unfortunately, this only seems to piss Tellu off and she seems ready to spank Chibimoon when the Pink One's keester is saved yet again by a well placed Sailor Pluto. Dead Scream tears Tellu apart.