Lee Hyun Wook (Rain) is a brilliant music producer, but due to a traumatic accident that took the life of his girlfriend, his heart has never been able to recover. Since then, each day has been a struggle to keep up appearances as the CEO of a top talent agency, until Yoon Se Na (Krystal Jung)—his beloved girlfriend’s little sister—moves to Seoul with hopes of making it big as a songwriter. As music soothes their shared wounds, both Hyun Wook and Se Na also discover the inspiration to fall in love with one another. Also starring Cha Ye Ryun, Krystal from Heirs, and Infinite's L and Hoya! Watch drama online for free.