The story begins with ChibiUsa coming home from school. Ikuko offers her some after-school snacks- donuts, lemon pie, and chocolate. For dessert, Usagi, ChibiUsa, and Kenji are given pudding and ice cream. Then, Ikuko gives Usagi and ChibiUsa chocolate fudge and crampuffs before they go start their homework.

The next day, ChibiUsa is in pain as she walks to school. Momo offers her some soda, but when ChibiUsa drinks it she spits it out in pain. Ami checks out ChibiUsa, and discovers that she and Usagi have cavities. ChibiUsa never heard of cavities in the 30th century. Rei explains that a cavity is a hole in the tooth that hurts. Minako says that cavities cause the jaw to melt. Once Ami mentions going to the dentist, Usagi cringes, then grabs Ami and cries. Usagi blames Ikuko, who tells the girls that she warned them about not brushing. She asks Kenji to take the girls to the dentist, which sends Usagi wild with fear; she cries on her bed and then tells ChibiUsa that the dentist is a scary place and that she is mistaken if she thinks she can come home alive.

The next day, Kenji takes the girls to the old dentist building. On the way in, they see two kids mumbling in pain after seeing the dentist. The dentist, an old creepy man, removes a tooth from a patient as Usagi and ChibiUsa watch. He ties a string to the tooth, then ties the other end to the door. He shuts the door, and the tooth is pulled out. A hysterical Usagi runs out of the dentist office, while ChibiUsa grabs a tree and refuses to let go. Kenji takes them out for ice cream to settle their nerves and tells them that they will see the dentist the next day. Then they walk home a bit disappointed; Usagi expected a cute dentist and Kenji expected a pretty assistant. That night, Regin the ghost appears. She haunts dentist offices and lives off of the pain caused by cavities. She casts a spell on the dentist offices so she can make more cavities.

The next day, Kenji picks up the paper after his morning jog. A paper falls out of the news, it is an advertisement for the new and improved dentist office with a brand new dentist. Minako calls Usagi and tells her about the ad; the ad features a picture of a cute new dentist. Minako says she will come with them since she has cavities too. The group enters the dentist office; Regin dressed as a pretty assistant asks how many people will be serviced and brings the group desserts and drinks while music plays in the waiting room. Diana finds this seems strange. The desserts make everyone sleep, and ChibiUsa is called first. She sits in the dentist chair, which is shaped like an elephant. Suddenly, metal cuffs bind her wrists and torso to the chair. Regin tells ChibiUsa that it isn't fair to single out one tooth, so she will give her an injection that will give all of her teeth cavities. ChibiUsa screams for help, and Diana bursts in with a piece of cake, which she tosses in Regin's face. Then she sets ChibiUsa free, and ChibiUsa yells, "MOON CRISIS MAKE UP!" to transform into Super Sailor ChibiMoon. Regin uses the dentist tools to create a noise that hurts ChibiMoon's tooth. ChibiMoon cries, and the crystals on her odango let off ultrasonic waves, which shatter some glass and hurt Regin. The dentist tosses a bunch of desserts at ChibiMoon, and ChibiMoon tries to eat as many as possible. Diana wakes Usagi and Minako, and seconds later Sailor V and Super Sailor Moon come in. They toss cake at the machinery to make them melt, and ChibiMoon finishes off Regin with the power of Pink Sugar. The new dentist building turns into the old dentist office, the cute dentist turns into the old dentist, and Kenji dreams he is sleeping with his head resting on the cute assistant's lap.

Usagi and ChibiUsa have their teeth removed, and when ChibiUsa goes home, Ikuko offers her snacks that build chewing power- dried squid and fish and raw vegetables.