A mysterious man, Dean, returns to his hometown of Grimsby after many years abroad in the Army. His arrival is met with animosity, particularly from his father, an avid pigeon racer. Dean is drawn back to confront his demons, and confess a secret to a childhood friend, Jess, only to discover she has been struggling since the untimely death of her husband. Whilst attempting to raise her child and battling a crumbling economy and dearth of opportunities, she is pulled into a harsh underworld. Dean must help her, throw her a lifeline, but the situation only darkens. When their lives are threatened he will do all it takes to make sure she is safe.

每一天对于克里斯汀（妮可·基德曼 Nicole Kidman 饰）来说都是完完全全崭新的一天，20年前的一场可怕的车祸让她的记忆定格在了那一天，脑部受到的严重损害令她的记忆只有24个小时，对于克里斯汀来说，每一天，她都在一张陌生的床上醒来，身边躺着一个陌生的男人，而这个陌生的男人是她的丈夫本（科林·费斯 Colin Firth 饰）。
　　每一天，克里斯汀都会和负责治疗自己的医生纳什（马克·斯特朗 Mark Strong 饰）通电话，在纳什医生的帮助下，克里斯汀渐渐拼凑出了自己的历史，原来，每一天即将结束之时，克里斯汀都会将这一天发生的事情写进日记本，但渐渐的，克里斯汀发现，日记本上所记录的内容，和本告诉自己的大相径庭。而某一日，当克里斯汀再次打开日记本时发现日记本里写了一句话：不要相信本