故事讲述准母亲吴静孕有一个患上先天性心脏病的胎儿，此症国内并无治疗成活的先例，消息立即引起传媒关注。曾雨桐 (左少青 饰) 被派往采访吴静及其丈夫，日夜守候期间，目睹两人为应否将胎儿诞下作出决定的矛盾及坚持时，激起自己对过去的感叹。原来她在出生一个月时，被母亲遗弃于修道院门外，一直被修女曾嬷嬷 (叶童 饰) 扶育成人。

　　就在采访期间，雨桐接到好友志轩 (吴奇隆 饰) 的电话，曾嬷嬷重病住院，时间无多。嬷嬷临终前将一个包裹及一张车票给予雨桐，希望她能对母亲的仇恨抛开，与她重聚。望着车票及嬷嬷的遗愿，令痛恨母亲的雨桐在爱恨间难以决断。

　　正在犹豫是否要踏上寻母之路时，雨桐遇上一位带着抑郁症儿子小丁上班的计程车司机。言谈间得知他对养育儿子的坚持，使对亲情不信任的雨桐心里泛起涟漪，对母亲当日抛弃自己的决定亦起了莫大的好奇，决定与志轩踏上寻根之路，希望解开昔日母亲狠心抛下自己的真相。

Abandoned as a baby, journalist Yue has only resent for the parents she never knew. While covering a tragic story about a woman and her unborn child, Yue receives news that her foster mother is dying. Her final wish is for Yue to meet her birth mother. With only a train ticket as clue, Yue embarks on a sweeping journey through China to find her mother and the truth behind her abandonment.