The story revolves around a Japanese girl named Mayumi, who is horribly disfigured in a sulfuric acid attack by her sister's ex-boyfriend. After the tragedy, Mayumi's family falls apart, and she is left to deal with the trauma and social isolation. Mayumi develops a dark alter ego, driven by a desire for revenge against those who wronged her.
She eventually becomes a vengeful spirit, known as "Kuchisake-onna," or the "Slit-Mouthed Woman," who terrorizes people by asking them if they think she is beautiful. If they answer "no," she kills them. The only ways to escape her are to answer her question with the same question, ignore her, or offer her a sweet.
The story is loosely based on real events that took place in Japan in 1978, surrounding a serial killer who murdered 13 people. However, the case remains unsolved, and the true identity and whereabouts of the killer are still unknown.
Here are the key facts extracted from the text:
1. The story is set in March 1978.
2. Mayumi Sawada is a student who is proposed to by a boy, but she rejects him.
3. Mayumi has a crush on her senpai (upperclassman), who is the captain of the athletics team.
4. Mayumi's ex-boyfriend had been stalking her and pours sulfuric acid on her face.
5. Mayumi's mother tries to stop the ex-boyfriend, but he kills her.
6. Mayumi's father kills the ex-boyfriend and then takes his own life due to depression and debt.
7. Mayumi undergoes surgeries to fix her face, but it will never look the same.
8. Mayumi becomes isolated and alone, and starts to see apparitions of a woman in a red jacket.
9. Mayumi's friends distance themselves from her, and she is bullied at school.
10. Mayumi's senpai breaks her heart by telling her he only sees her as a little sister.
11. Mayumi discovers that her senpai is dating another girl.
12. Mayumi's sisters find evidence of her crime and try to attack her.
13. Mayumi's sister puts poison in her breakfast, but Mayumi doesn't die.
14. Mayumi's sisters try to kill her, but she wakes up transformed into a vengeful ghost.
15. Mayumi's ghost starts to haunt and kill people, including her sister and the boy who proposed to her.
16. The story is based on real events that happened in 1978 about a serial killer in Japan.
17. A client of a hair salon identified Mayumi as a suspect, but there was no conclusive evidence.
18. Mayumi disappeared and her whereabouts were never known, and the case remains unsolved.