: Simultaneously, Hayeong comes to live with Seonkyeong and her husband, Jaeseong, after her maternal grandparents die in a suspicious house fire. Seonkyeong begins to notice unsettling behavioral parallels between the young girl and the serial killer, including chilling detachment and sudden violent rages. Key Themes & Motifs
The novel intertwines two primary story arcs that Seonkyeong must navigate:
The book is frequently described as a blend of The Silence of the Lambs and The Bad Seed .
: Yi Byeongdo, a condemned killer who has been silent for years, suddenly requests an interview specifically with Seonkyeong. As she delves into his past, she uncovers a history of childhood abuse that shaped his violent path.
: Both the killer and the child use manipulation to unsettle Seonkyeong, with the killer even offering her "advice" on how to handle the girl. Characters
(English title: The Only Child ) is a psychological thriller by South Korean author Seo Mi-ae . It centers on Seonkyeong , a criminal psychologist and university lecturer who finds herself simultaneously investigating a notorious serial killer and managing her increasingly disturbing 11-year-old stepdaughter, Hayeong . Core Narrative & Parallel Plotlines
: The narrative explores how hidden family secrets and past abuse can manifest in the next generation.