Beomgyu is mute after a traumatic childhood incident. He can hear others, but does not speak. Beomgyu can communicate with others using sign language, but no one can hear his voice. Because of this, he doesn't get along with teenagers his age and changes schools because of which he gets bullied.

Beomgyu transferred to another school where history repeated itself. His classmates look at him strangely, and his teachers avoid contact with him. But among them there is one guy named Choi Yeonjun.