A murder occurs, and Hong Yi Young, a timpanist with insomnia and a simple mind, can't remember what happened that day. She meets Jang Yoon, a pianist in the orchestra who is bad at singing. To help her sleep, Jang Yoon calls her every night, and together they try to uncover the truth about the murder.
Meanwhile, Nam Joo Wan, a charismatic orchestra conductor, and Ha Eun Joo, an arrogant violinist, play
