A touching drama about the power of love. Moon Ha-won, an exceptional programmer, has suffered for years from unrequited love for his childhood friend Kim Ji-su. After developing a device based on artificial intelligence, he decides to imbue it with the memories and voice of his beloved. However, a few years ago, Ji-su cut off all communication with Ha-won. By a twist of fate, Ha-won meets Han So-woo, a charming and kind sound engineer. So-woo is deeply moved by her new friend's story and decides to help Ha-won. Unaware of how her life will soon change, she records Ji-su's voice.