故事发生在人才辈出的音乐艺术学院之中，学习大提琴的郑宇（金政旭 饰）拥有着高于常人的天赋，对和音乐有关的所有事情都极为严苛。明振（林智奎 饰）是郑宇的好友，和郑宇不同，明振天资平平，却因为其在功课上的努力和散发出来的热情而打动了老师和听众。此外，两人还拥有一个共同的朋友智恩（徐贤贞 饰）。

A noise is coming from the floor upstairs. Eunsu, hears this for over a month which causes uncontrollable anger to rise up. She gets eliminated again from a competition she had prepared for a long time. Eunsu decides to write her last piece with the theme of the noise between the floors and persuades her friend to help her follow and track the secret.