Two detectives teamed up to catch a serial killer who murdered their family. Moo Jin Hyuk's life spiraled out of control after his wife was murdered. He starts to put himself together after he meets Kang Kwon Joo, US-graduated voice-profiler, who lost her police father to the same serial killer. They work together on the 112 (emergency telephone number) call center team.

Top actor Ji Eun-ho hires ghostwriter Seo Jung-eun to write his autobiography. Eun-ho is tense, irritable and difficult to work with, but Jung-eun finds her assignment fascinating because Eun-ho claims he began acting not because he wanted to become a star but because he thought being in the limelight would help him find his first love, Ji Eun-dong. Eun-ho and Eun-dong's complicated romantic history has spanned two decades, and he's convinced that he can never love anyone else. As Jung-eun helps him remember Eun-dong and why he lost her, Eun-ho (whose birth name is Hyun Soo) looks back on his memories of her, from when he met when he was seventeen.