Summer Thomas questions her own sanity when violent patient, Lucy Clark, disappears from a locked hospital ward... because no one else will admit that Lucy exists.

As Summer digs deeper into the disappearance, it becomes apparent that Lucy is looking for her too, but Summer should have stayed away.

Now, Lucy is coming for her... and there's no escaping someone who doesn't exist.

A gripping and addictive debut with a shocking twist that will send shivers down your spine!