本片改编自王朔小说《过把瘾就死》。
杜小桔（徐静蕾）和王毅（佟大为）结婚后，相识、恋爱中被遮蔽在阴影里的问题全曝光在了阳光下。杜小桔认为爱情高于一切，婚姻更是爱情的立方级，“神经兮兮”地整日要王毅说“我爱你”，王毅认为爱情同请客吃饭没本质区别，结了婚爱情有或没有是一回事，最烦的事是张嘴对杜小桔说出“我爱你”。于是，杜小桔的吃醋和找茬成了一剂剂调节两人平淡婚姻生活的佐料，而她的反目和出走，则是不想让日子越流越成死水。

Peking, 1948. A winter night. A man returns home to find a letter awaiting him written by a woman before her death. in the letter she tells him the story of her love for him -a life-long passion that has not diminished over time, but one that he has never known. her story spans 18 years from the moment she -then a 13 year-old girl- sets her eyes on her new neighbor. she tells their brief but passionate love in her youthi the hardship she goes through raising their child alone, and their final encounter after the war, during which the man fails tor ecognize her and one which leaves her in despair. Now having lost her son, she no longer has the courage to live on. Only in a letter is she capable of telling him everything, for the first and the last time. shaken by the letter, the man searches his memory for the nameless woman.

After Xiao Yu's mother died in an accident, she moved back to live with her birth father who she knows little about. Gradually, they grew to know each other and to accept each other for who they are.

A stylish urban romance about the silent suffering of a modern Chinese couple.