The play tells the secret of a woman who can only fall asleep by listening to the tuneless singing, the truth of the horrific murder buried in the woman's lost memory, and the unique suspenseful love story of rediscovering the traces of love. Yeon Woo-jin plays Jung Yoon, a mysterious tone-deaf worker who is also a guest pianist of the Hakyo City Symphony Orchestra. He is an excellent, willful, free-spirited and loyal person who does not care about rumors and other people's eyes. His piano playing is very beautiful and can capture the conductor's heart at once. Kim Se-jeong plays the role of Hong Yi-young, the auxiliary timpanist and unemployed student of the Hakyo City Symphony Orchestra. With a plain and ordinary appearance, she is a timpanist who suffers from insomnia and nightmares. She can't even fall asleep without sleeping pills. Song Jae-rim will play Nam Joo-wan in the play. He is an associate professor of the music department and the conductor of the city symphony orchestra. He is a cute and charming person with an artistic temperament. Park Ji-yeon plays Ha Eun-joo, the second violinist of the Hakjo City Symphony Orchestra and the heroine's college classmate. She is sexy and hot, a cheerful and lively "queen of life". She knows the past of Nam Joo-wan (played by Song Jae-rim) and the true face of Jung Yoon (played by Yeon Woo-jin).