High school senior, Anna Faraday, has a remarkable singing gift that liberates something inside people, and yet, she is stuck living cautiously after a fatal accident took her brother's life. The one thing that tempts her to break free and take a risk is Chase, the hot new American guy in her grade. When a simple trip to the high school physics department sees her targeted for her voice, and a reckless car drive ruins the most romantic night of her life, Anna is then forced to sing for a secret frequency-based experiment that goes wrong. Left fading from existence, she is thrust from her carefully measured world into a terrifying reality that leads her to seek help from Rennie Parker, the last guy she ever thought she'd ask-a guy invisible to her, until then. Now the one unseen and unheard, Anna knows time is running short. Will Rennie, or anyone, understand what's happened before she disappears forever?