The following version of this book was used to create the guide: Yi, Esther. Y/N. Astra House, 2023.

Esther Yi's novel Y/N is told from the first person point of view of the unnamed protagonist and narrator. Because the novel traces the narrator's mounting obsession with an international K-pop star, Y/N often subverts narrative logic and the conventional plot line. To enact the narrator's delusional state of mind, the author toys with point of view and form, language and tense. For the sake of clarity, the following guide relies upon the present tense and a linear mode of explanation.

The narrator lives with her flatmate Vavra in Berlin, Germany. Ever since moving in with Vavra, the narrator has ignored her flatmate's pleas for her to attend a K-pop concert. The narrator prefers to spend her time writing freelance and reading and studying alone.

However, when Vavra's friend gets sick and cannot attend the concert with her, the narrator agrees to go. When they arrive at the arena, she feels lightly curious about the experience of following a Korean boy band. No sooner have the performers come on stage, the narrator is overcome by passionate feeling. She is immediately drawn to the one member, whose stage name is Moon. Because his lyrics resonate with her, she believes he is singing directly to her.

The narrator starts to obsessively follow Moon online. She becomes particularly attached to his livestreams. Over time, she is sure that she and Moon are in love and that Moon is a better romantic partner than her boyfriend Masterson. Masterson tries to get the narrator to see that she is only Moon's fan and that Moon is only a figment of her imagination. However, the narrator refuses to hear Masterson, and they break up.

After they break up, Masterson sends the narrator a reference for a therapist named Dr. Fishwife. In their only session, Dr. Fishwife assures the narrator that she is not in love with Moon. If she were, she would already be in Korea looking for him. The narrator ends her video call with Dr. Fishwife and buys a ticket to Seoul.

Shortly after arriving in Seoul, the narrator meets a woman named O. O feels drawn to the narrator because she made the soles of the shoes the narrator is wearing. She gives the narrator a ride on her moped and promises to help her find her lover, even if he does not yet know that she exists.

O brings the narrator to Polygon Plaza, a space designed by the boy band's manager, the Music Professor. The professor wanted to give the boys a place where they could learn and grow as individuals and intellectuals. Throughout her time in the space, the narrator cannot focus on her surroundings, because she is so desperate to find Moon. The Music Professor urges her to let go of her fantasies, but the narrator prefers to live in her imaginary world.

The narrator travels from Polygon Plaza to a place called the Sanctuary. A woman called the Caregiver runs the facility. She gave up her own desires and dreams to devote her life to her three residents, Mister Goun, Miss Lina, and Mister Suguk. The narrator largely disregards the residents during her visit, because she is convinced that Moon is at the Sanctuary. Throughout her time here, she wanders the halls in desperate search of the object of her desire.

When she finally meets Moon, she is shocked to discover that he and Mister Suguk's daughter Maehwa are in love. The narrator tries to convince Moon otherwise. She shows him a piece of fiction she wrote about him, in hopes that the story will help Moon understand the profundity of their connection. Moon disregards the story, and informs the narrator that she is just like all of his other fans. After the narrator finds him and Maehwa sleeping side by side shortly thereafter, she leaves the Sanctuary.

Unsure what to do or where to go, the narrator travels to O's apartment. O seems different to the narrator, and reveals that she has fallen obsessively in love with a new man. She and the lover have made a video together, but O has abandoned her private painting practice. The narrator leaves O's room and stands on the balcony. She smells a fire, but can find no evidence of its existence.