While walking home one night, Momoko Takikawa has a bucket of foul-smelling liquid poured on her by a mysterious woman. When she makes it home, she manages to peel the drying substance off of her skin, but is forced to cut her hair short. The next day, at her job as a kindergarten teacher, Momoko has to deal with Chikara Kawabe, an antisocial boy with a tendency to scratch other kids when provoked. He also has a terrifying appearance, which scares his classmates.
Later that day, Momoko has to stop Chikara from, once again, destroying all of the class paintings on the walls, which he calls "peeling".
Eventually, Maya Kawabe arrives to pick him up from kindergarten. Momoko asks to walk home with her so that she can discuss Chikara's behavior. Maya agrees that his behavior might have to do with his father recently passing away. When they reach the Kawabe residence, it turns out the woman who picks up Chikara from kindergarten is really his aunt. When Momoko talks to Chikara's mother, she finds out that Chikara is constantly ripping the wallpaper off of the walls. She also notices that his mother never has any particular expression on her face and seems "off".
The next day, Momoko's boss tells her that other parents have been complaining about Chikara's violent behavior towards their children and if it doesn't stop soon, she'll have to do something about it. Momoko goes outside to look for Chikara and finds that he scratched a lot of skin off of another child. This causes Chikara to be expelled from school. However, he continues to come to school and leer inside the windows. Momoko tells him to go home, but he tells her that he doesn't want to.
Sometime later, Chikara follows Momoko home. Momoko's father is visiting and, after examining Chikara, he sees that the boy's skin is so thin and damaged that he no longer has fingerprints. Momoko then drags Chikara home to his mother, who doesn't seem to be worried about him at all. She tells Momoko that she believes Chikara will be a good-looking boy soon enough.
That night, Chikara's mother and aunt prepare a strange chemical in the kitchen. His mother says that she doesn't want it to fail anymore and then drags Chikara over to a table, where she and Maya cover him in the substance. When it sets, his mother excitedly peels it off. After an hour, his mother realizes that there's no change in her son and gets angry. Maya attempts to convince her to stop doing this to Chikara, but his mother won't listen and instead scratches off the wallpaper while shouting about how she wants to see her son's "true beauty".
Momoko, having walked her father to the train station, sees another woman being splashed with the same chemical that was poured on her. She chases after the culprit, finding out that it's Maya. Momoko asks her what's going on and Maya tells her. It turns out that the chemical was created by Chikara's father as a beauty medicine. While his mother used it and loved the results, she's now attempting to use it on her son, not knowing that Maya secretly changed the ingredients so that it wouldn't work. Maya then started throwing it on strangers in order to get rid of it. Momoko doesn't believe her, but can't stand seeing Chikara being abused.
Meanwhile, a woman in a hat and cape walks down the street. She asks a passing businessman to tell her if she's beautiful. Horrified, the man runs off screaming while the woman laughs.
Maya attempts to convince Momoko to leave their house before Chikara's mother returns. Suddenly, the woman in the cape runs up to both of them and bashes Momoko in the head with a rock, knocking her unconscious.
As she wakes up, Chikara's mother explains what's going on. Her husband, in order to find an elixir for eternal youth, created a medicine that could be spread all over the body. After seeing the results, he died of fright. However, his wife believed that what he found was true beauty, and now she wants to spread that beauty to her son. While explaining the ingredients, she accidentally spills acid on her skin. She hurridly asks Maya to pull the zipper on her back. This causes her skin and hair to fall off, revealing her muscles and tendons. As Maya washes the acid from her skin, Kawabe tells Momoko that the chemical seperates the skin from the muscles, which is what caused her husband to die of fright. She must keep her skin soaked in a saline solution at all times so that she won't dry out. While picking up the acid bottle, she notices that it doesn't have the same smell the acid has. It turns out that Maya replaced the acid with plain water.
Chikara finds the real bottle of acid. Kawabe begs him to give it to her, but instead, he opens the bottle, knocks over the water tank containing his mother's skin, and then pours the acid over it, completely destroying the skin. Panicking, Kawabe screams at Maya to give her her skin and then rips the skin from her face. Angry at seeing his aunt hurt, Chikara grabs two of his mother's muscles and rips them apart. While Kawabe lies on the floor in agony, a now skinless Maya tells Momoko that she was tricked into using the chemical three years ago and is now dying. Shocked from the events of the past few minutes, Momoko faints back into unconsciousness.