Around six to 15 percent of all people (study by John Hearst 2011) hear voices at some point in their lives. Many of them even live with their invisible companions for their entire lives. Well over half of voice hearers are mentally healthy and lead a completely unremarkable life. Despite this, voice hearers continue to be stigmatized and are subject to prejudice. As a result, few speak openly about their experiences. In recent decades in particular, however, voice hearing has been regarded as a symptom of impaired brain function. The documentary sheds light on the phenomenon. Sufferers describe the voices in their heads, as well as the thoughts and feelings they trigger in them, and scientists explain the causes that lead people to hear voices.