Jemma is a young librarian in a comfortable rut. One night, without warning, the world goes mute. Every person in every country is rendered unable to speak.

Jemma thrives, a little too well. Soon, she's being watched, and she and a new friend are in danger of disappearing from their lives completely.

Faced with the choice to cling desperately to old methods of staying safe or to find new ways to survive, Jemma leaves her comfortable library behind, entering a world in which certainty and safety are nowhere to be found.

Jemma is no longer -just- a librarian. She's at the center of a project that could mean life or death for the entire human race. She and Jack must find a way to change what they know to be true, to overcome pain and setbacks and save not only themselves, but also everyone they care about. They'll take on their biggest fears in this thrilling conclusion to the Muted Trilogy.