The following version of this book was used to create the guide: Kim, Ae-ran. My Brilliant Life. Macmillan Publishing Group, LLC, 2020.

Ae-ran Kim's novel My Brilliant Life is told from the main character Areum's first person point of view. The novel is written in the past tense and embraces formal atypicalities, including fragmentation and temporal distortion. The following summary relies upon the present tense and a linear mode of explanation.

Not long after 16 year olds Mari and Daesu start seeing each other, Mari discovers that she is pregnant. Because her father dislikes Daesu and because she is so young, Mari does not know what to do. Even after the doctor urges her to give birth because of her preeclampsia, Mari continues wrestling with the decision. Finally she begins to fall in love with her growing child. She and Daesu marry and move in with her family. Daesu gets a job in construction in order to support his family. He grows more excited about life and his new baby, who they name Areum.

When Areum is born, he appears healthy and strong. Mari and Daesu, though struggling, gradually adapt to life as young parents. Then, when Areum is two, they begin to notice that something is wrong. After taking him to several doctors, they learn that he has progeria. The condition causes the body to age at an uncommonly rapid pace.

When Areum turns 16, everyone declares him a miracle. It is very rare for anyone with his condition to live to this age. Areum knows that this is medically surprising, but is reluctant to call himself remarkable. He often feels lonely. Though he is a teenager, he cannot connect with people his age. Though he looks old, he lacks the same experiences as the elderly. He spends most of his time reading books by himself.

After returning from a stint in the ICU, Areum decides that it is time for him to write a story of his own. He plans to record the story of his parents' early life, and give it to them when he turns 17. One night while working on the manuscript, he overhears his parents arguing about money. The next day, he tells them that he wants to go on his mother's friend Chae Seungchan's television show. His parents eventually agree. During the interviews, Areum and his family describe Areum's condition. Areum tries to convey what his life is like. The show works, and Areum's family receives a wealth of donations, which pay for his hospitalization.

One day, Areum discovers an email from a viewer. The viewer's name is Lee Seoha. She says she is also 16 and is also living with a terminal illness. She and Areum begin communicating via email. Over the course of their correspondence, the new friends grow closer. Then one day, Seoha stops responding. Areum soon learns that Seoha is not a teenage girl, but a 36-year-old man. Devastated, Areum retreats into the world of the video game LittleBigPlanet. Once he finally wins the game, he loses his sight. Not long later, he senses that the end of his life is near. He tells his parents he will miss them, and lets go of his old hurts and disappointments.