According to legend, grim reapers and angels started a war upon discovering an ultra-powerful genesis piano—destroying it and scattering the keys throughout the cosmos in the process. No one has seen a grim reaper or an angel since. Enter Xiaochao, a cursed human girl just trying to make it through high school in one piece. One day, she stumbles upon Michael, an angel hiding in plain sight, playing a gorgeous tune on the piano in the school's music room. When she later sneaks into the music room and plays a single note, the windows shatter, and in walks a grim reaper, masked as a teacher. They say two's company, but three's a crowd. Will these three find harmony in romance? Or will they just crowd each other out?