Sound of Sign

Suffering from the loss of communication because of her stammer since she was a child, Kacy got used to role-playing as a deaf to avoid trouble.
After an acquaintance with her neighbor Nate, who kept building one-way communication with her with sign language, Kacy went all the way to learn the language to cover her lie. Finally, they managed to understand each other, but Kacy was too shocked to find out the reason why Nate started to learn how to express without talking...
What's untold behind the silence them?
(Source: microfilm-music.hk)