Steffi has been a selective mute for most of her life. The condition's name has always felt ironic to her, because she certainly does not "select" not to speak. In fact, she would give anything to be able to speak as easily and often as everyone around her can. She suffers from crippling anxiety, and uncontrollably, in most situations simply can't open her mouth to get out the words.
Steffi's been silent for so long that she feels completely invisible. But Rhys, the new boy at school, sees her. He's deaf, and her knowledge of basic sign language means that she's assigned to help him acclimate. To Rhys, it doesn't matter that Steffi doesn't talk. As they find ways to communicate, Steffi discovers that she does have a voice, and that she's falling in love with the one person who makes her feel brave enough to use it. But as she starts to overcome a lifelong challenge, she'll soon confront questions about the nature of her own identity and the very essence of what it is to know another person.