A telepathic boy named Kōtarō, once known as the most beautiful boy of the millennium, caused a legendary incident during a live television broadcast as a child. Ten years later, high school student Ikeda Minori meets him and is drawn to his kind and cool demeanor, unaware of the deep secret he carries. The story unfolds in a modern Japanese high school setting where Kōtarō and Minori join the Supernatural Phenomena Research Club, led by eccentric upperclassman Kajii Keiji and his quiet childhood friend Matsushita Maka. As Minori falls in love, she begins to sense that something is off about Kōtarō, who seems to know what she is thinking before she speaks. The narrative slowly reveals that Kōtarō is not only a telepath but also possesses the ability to manipulate and erase memories. Another telepath, Maka, initially warns Minori against trusting Kōtarō, driven by her own traumatic experiences with the ability. A major arc involves a troubled upperclassman named Kawamoto and a popular couple on campus, leading to Minori discovering that Kōtarō’s past includes a traumatic encounter with a older telepath named Haruki, who committed suicide in front of Minori when they were children. To protect Minori from that horror, Kōtarō erased her memory of the event and of ever meeting him—the central "lie" of the title. The later parts of the story see Kōtarō’s telepathy worsening into a dangerous neurological condition, threatening his life. He travels to the United States for treatment, accompanied by Maka, while Minori waits for him. After years of separation, Kōtarō returns, supposedly cured, but it is revealed that his powers have instead evolved into a more advanced form. He and Maka deceive the research team to secure his freedom. Back in Japan, Kōtarō chooses to continue lying to Minori about his remaining abilities, living a seemingly ordinary life with her while quietly protecting her from the truth. The story closes with the theme that his entire existence has been a protective lie, and he will carry that lie forever to preserve her happiness.