Sang-woo managed to survive a car explosion but lost his memory in the process. With the dedicated care of his wife, Yoon-hee, he was able to resume a normal life. Despite this, Sang-woo begins to feel disconnected from the person he once was and the version of himself that Yoon-hee describes. His suspicions grow, especially after discovering that Yoon-hee had been unfaithful. This revelation drives him to obsessively seek out the truth about his past. As a mysterious man starts shadowing him, Sang-woo’s confusion deepens. He is left wondering, “Who was I in those forgotten memories?” Ultimately, a startling truth comes to light.