Waves Upon Waves summary:

there's an old legend in Sereong's family: their flute 'Manpa' will turn into a person if you care for it with enough love! But Sereong doesn't believe in this legend and plans to sell Manpa.... But it was then when Manpa turns into a human and tells Sereong he can grant her wish.A romance between one who grants miracles and one who doesn't believe in miracles.