Also titled "The Woman With No Ribs." A one-shot story.
Yuki is so ashamed of her figure that she refuses to go swimming, either at school or on the beach. She believes her ribs look strange, and hears that she can have plastic surgery to alter the appearance of her ribcage. Yuki goes to a nearby clinic that performs the procedure, but is told that she must pass a mental health assessment before she can have the surgery.
As Yuki leaves the clinic, she runs into her brother's girlfriend Ruriko. Ruriko is very distressed at hearing a creepy, echoing melody that she hears every night. It gets right into her head and causes her chest pains. Yuki hears it too, so the following night, she and her brother Keisuke go to Ruriko's house to listen for it. The music begins, and they follow the sound to a park, where a mysterious woman is playing a stringed instrument. However, she runs away when she sees them, dropping her instrument.
Yuki and the others examine the instrument but find that it doesn't work - there is nothing to make the sound resonate. They wonder how the woman was able to make music with it, and realize the instrument is made from a rib bone. Keisuke thinks it's an animal bone, but Ruriko suddenly panics and destroys the instrument.
Shortly afterwards, Ruriko disappears. Her corpse is found with all her ribs torn out. Yuki is sure that the murder is connected to the woman and her rib bone instrument. Despite this, Yuki goes ahead with the surgery to shrink her waist by removing some ribs. As she lies drowsy on the operating table, the doctor tells her he has only performed the procedure twice before: once on Ruriko, and once on another woman who turned out to be psychologically unbalanced. Despite knowing better, he complied with her instructions to remove most of her ribs. When Yuki awakens after the surgery, she's not sure whether or not she dreamed the doctor's words.
Subsequently, Yuki begins to hear a creepy melody similar to the one Ruriko heard; and to feel pain in her ribcage. She is compelled to go into the forest, where she runs into the woman, playing the same kind of instrument as before. The woman explains that the instrument is made from one of Yuki's rib bones removed during surgery. It resonates against the woman's chest because she lost so many of her ribs that the doctor had to replace them with metal wires. The woman takes off her shirt to reveal her fully exposed internal organs, surrounded by wires.
At this point, the doctor appears. He and the woman pursue Yuki with a pitchfork. Keisuke arrives, having apparently followed Yuki. He fights off the doctor; but the woman escapes. Although she is never found, her music continues to be heard around the town.