The story begins with ChibiUsa being introduced by her teacher to her new class as Serenity. The class whispers about her funny name and funny hair. ChibiUsa is seated next to a nice girl name named Momoko. A boy seated near ChibiUsa named Kyusuke teases ChibiUsa about her small size, and Momoko tells him to stop. ChibiUsa notices Kyusuke has a Sailor V badge, and Kyusuke says it is a one-of-a-kind since his sister made it. Kyusuke says ChibiUsa can have it if she does everything he says, but ChibiUsa holds her ground. Momoko asks if ChibiUsa has a nickname, and Kyusuke says he heard that another girl named Serenity lives with ChibiUsa, which he finds weird. ChibiUsa tells them her nickname is ChibiUsa, which everyone thinks is cute. ChibiUsa sees a girl sitting on the other side of the room, and Momoko says the girl is Ririka. A boy named Sorano Gurio says that Ririka is the daughter of an ambassador staying in the embassy. Ririka sways dizzily, then asks a boy named Ishihara to walk her home since she is feeling dizzy. As Ririka passes ChibiUsa, ChibiUsa notices Ririka's strange smell, like perfume.

That night, the family asks ChibiUsa about school as ChibiUsa does her homework. The assignment is a picture diary. ChibiUsa draws pictures of all the students she met while telling the family about them. Momoko's family runs a Chinese restaurant, and the class will be in charge of the garden. Kyusuke's family runs a soba restaurant. Ririka is slim, pale, and popular with the boys. When ChibiUsa mentions the embassy, Ikuko says that the house is haunted because it has been abandoned for so long. Shingo says the yard is overgrown and creepy.

The next day at school, the teacher asks if anyone heard from Ishihara, since he is absent. One boy says points out that he walked Ririka home, but Ririka says he didn't say anything to her. When ChibiUsa glances at her, Ririka smiles back. Later, Momoko shows ChibiUsa the garden of the restaurant and the flowers that are wilting although they are fed and watered everyday. Ririka walks up and says the soil is bad. Then she pokes ChibiUsa's cheek and says her pink puffy cheeks look tasty. ChibiUsa and Momoko get nervous. Ririka leaves early again, this time with a boy named Kuwano. The next day the students chat about Kuwano, and the fact that he never went home. At lunchtime, it is ChibiUsa and Kyusuke's turn to serve lunch. a student tells the teacher that Ririka is missing, so she sends ChibiUsa and Kyusuke to find her. They find her eating flowers, which spooks them out.

ChibiUsa tells Usagi, Ami, Rei, Makoto, and Minako about Ririka, and Makoto says Ririka must be a vampire. Ami says that vampires are creatures that suck blood and strong-scented flowers are their favorite foods. Makoto says at the embassy on Sakashita, you can hear screaming each night, so it must be Ririka sucking their blood. Usagi gets the creeps. Makoto pulls the chocolate cigarette out of her mouth and says they should go out to eat. She says vampires can't stand garlic, and ChibiUsa should eat some garlicky food and see Ririka's reaction.Minako says Vampires live in coffin, and Rei adds that to kill them you must lay a cross on them and pound a stake into their chest. Usagi is even more freaked out now.

The next day at school, ChibiUsa asks where Ririka is, and her teacher says she is absent so she and Momoko must take her the homework. Momoko is scared, so Kyusuke volunteers to go with them. He makes Gurio come along too.

The kids walk throughh the yard, which is filled with the same flower Ririka was eating, as well as a bunch of graves. A hand touches ChibiUsa's shoulder, making her scream. It is Ririka's mother, who doesn't like ChibiUsa's garlic breath. ChibiUsa notices this. Ririka's mom invites them inside for snacks and says that the missing boys are probably tired out from playing and heading home, and that Ririka was probably eating a candied flower. Momoko eats a bunch of snacks before the kids leave. At this time, Ikuko tells Usagi and Minako to go pick up ChibiUsa. The kids realize they left Momoko behind, and go back for her. When they do, they see Ririka's mom sucking Momoko's blood. Everyone screams, and Ririka pops out of a coffin, feeling hungry. Ishihara and Kuwano also appear as vampires. A voice yells, "CRESCENT BOOMERANG!" and Sailor V's crescent moon boomerang hits Ririka's mom in the face. Sailor V and Sailor Moon appear and yell, "DOUBLE SAILOR KICK!" They kick Ririka's mom down as Ririka attacks the boys. ChibiUsa yells, "GARLIC ATTACK!" and uses her garlic breath to knock out Ririka (and the boys.) Sailor Moon uses her Moon Princess Halation to kill Ririka's mom, and Ririka turns into a flower, then wilts. That night, ChibiUsa dreams she is a Sailor Senshi.

The next day, Momoko thinks that the vampire episode was a dream and wishes she could have said goodbye. Kyusuke gives ChibiUsa a one-of-a-kind Sailor Moon badge for being so brave.