Desperate journalist Nick Bishop takes a job profiling new mindfulness app, Clarity. Relaxing meditations are mixed with haunting \'sleep songs\' where a woman\'s voice sings users into a deep sleep.Then the nightmares begin.Vivid and chilling, they feature a dead woman who calls Nick by name, whispering guidance - or are they threats?Soon, he can\'t escape her voice. And that\'s when he makes a terrifying discovery: no one involved with Clarity has any interest in his article. Their interest is in him.Because whilst he may not have any memory of it, he\'s one of twenty people who have heard this sinister song before, and the only one who is still alive...