As part of her recovery from a devastating car accident, Grace Thomas embarks on a surprise cruise booked by her husband, Cameron. The accident still haunts Grace and she is a little anxious to be leaving her family, but excited to fulfil what has been a life-long dream of hers - cruising around the Mediterranean with some girlfriends - even if her husband\'s secretary, Chantelle is tagging along for the trip. Maybe this is a chance to start a fresh with this woman. But Chantelle appears to be everywhere Grace turns, and her instincts can’t all be wrong. Something is off. Not only does Chantelle resemble Grace, it soon becomes clear that she is desperate for Cameron’s attention, but at what lengths would she go to get it? Were Cameron\'s motives for sending Grace away on this cruise as admirable as she first thought and is her husband\'s relationship with the ever-present Chantelle as platonic as he claims? Grace\'s journey of self-discovery suddenly begins to feel rather sinister. Her friends are distant, Chantelle is incessantly playing with her mind, and Grace feels more lost and alone than ever. Then, she discovers that her husband has told the children she’s died. Grace\'s world is shattered. Everything she knows has been a lie and the truth has devastating consequences for everyone...