Megumi is a 15-year old girl living in Sotoba. She always felt like she didn't fit in the village where everyone was closeminded, knew one another and criticized the way she dressed. She felt like she was better off in the city and it was her dream to go to the city and become an idol in show bussines where she would hang out in clubs every night. Her only friend in Sotoba is Kaori Tanaka, whom she actually doesn't like at all like the others. Megumi has an unrequited crush for Natsuno Yuuki, a guy the same age as her whom moved to Sotoba from the city. Like her, he also wishes to leave Sotoba and go to the city. Megumi writes him a late summer greeting card but she's too shy to post it. In her free time, she either takes walks around the village, showing off her dresses or she sits near Natsuno's bedroom window in the bushes admiring him from afar.
When a new family moves into the Kanemasa mansion, Megumi is intrigued. She decides to visit them but never returns home. A search-party is organized for her and after searching they discover Megumi's body deep in the mountain woods. The doctor concludes that she suffers from anemia but should be fine. However, a few days later, Megumi dies of heart failure, shocking everyone.
At Megumi's funeral, Kaori presents Natsuno the late summer greeting card that Megumi wrote for him but Natsuno refuses to accept it considering he wasn't really close to her. When burrying Megumi, Kaori leaves a present that she had planned to give Megumi for her 16th birthday in Megumi's coffin. After Megumi's death, Natsuno begins to hallucinate and thinks he still sees Megumi.
After receiving an invitation from Tatsumi to Tohru Motou's house, Megumi and Tatsumi visit late at night while Natsuno is staying over. Megumi enters Tohru's bedroom where both guys are sleeping. She says she hates Tohru for being closer to Natsuno than she ever was. She reveals her fangs and goes in for the bite. Natsuno wakes up covered in sweat and believes it was all just a bad dream.
When Tohru dies several days later, Natsuno knows that Megumi has risen from the dead. He gathers her friend Kaori and Kaori's younger brother Akira, whom both were already suspecting something of a supernatural nature was going on, to dig up Megumi's coffin and confirm if she was truly dead. And they are right, Megumi coffin is in fact empty causing Kaori to break down in tears.
After this, Tatsumi, whom had been spying on them the whole time, orders Megumi to go after Kaori and Akira's family starting with killing their father. She does so and threatens Kaori for being close with Yuuki despite knowing about her feelings for him.
Some days later, Natsuno also dies and Megumi hears a rumor that Natsuno is cremated because he originally came from the city. These news devastate her because she knows that Natsuno can't rise from the dead if cremated.
After the humans finally discover the vampires, a war breaks between the humans and the vampires. Megumi decides to escape and wants to go to the city. The humans were killing the Shiki during the day when they are vulnerable. Megumi hides her coffin in the bushes, deep in the mountain woods where she sleeps for the day. When the night comes, she goes with her plan of leaving for the city. When she reaches the final obstacle before being free, a group of villagers holding flashlights was near so she could never just cross the road. As the group gets distracted by seeing fire spreading around the woods, Megumi takes her chance. While crossing the road where she once used to wait for the bus with Yuuki, Megumi sees a nostalgic flashback of him waiting for the bus. She gets distracted by nostalgia, causing her to get caught by the group of villagers holding flashlights. She escapes into the darkness, running into a dark grassfield. Soon then, a bunch of tractors turn on their lights and locate her on the ground. She is ambushed by the humans who run over her with a truck. Megumi gets chased by the villagers but cannot run anymore so she tells them her plan and begs them not to hurt her. Megumi gets hit by a truck again, causing her to fall on the ground, getting her arm crushed. Megumi is still alive and tries to escape. In the anime, her head is crushed by an incoming tractor and Megumi is then staked by the humans. In the manga, Megumi gets hit by a car and then gets staked with around five stakes sticking from her chest. As she is dying, she thinks she made it to the city and sees a vision of Laforet and Harajuku, but it was actually just a magazine of hers near her head. She dies happy thinking about the fun life she is going to have in the city, which puts her at peace, indicating her soul has been set free, as is the case with other vampires. Megumi's death is symbolic. It shows how the close-minded people can't accept something different, and they tend to destroy it. They destroyed her in such a gruesome way for simply being different and punished her for it. Megumi was the antithesis of Sotoba.