为了N

2004年的圣诞夜，某高级公寓内，野口贵弘（德井义实 饰）及其妻子奈央子（小西真奈美 饰）双双遇害，现场则有四个惊慌失措的年轻人：杉下希美（荣仓奈奈 饰）、成濑慎司（窪田正孝 饰）、安藤望（贺来贤人 饰）和西崎真人（小出惠介 饰）。最后西崎认罪，入狱服刑十年。曾经在濑户内海某小岛担任驻警的退休刑警高野茂（三浦友和 饰）对此案存有诸多疑问，当年出生在该小岛的希美和慎司曾卷入神秘的失火事件，上京后的希美与安藤是大学同学，两人又和西崎租住在同一公寓中。千丝万缕将四个年轻人以及野口夫妇联系在一起，每个人都有需要守护的“N”，他们用谎言编制了扑朔迷离的爱恨迷局…… 　　本片根据凑佳苗的原作改编。University students Sugishita Nozomi, Naruse Shinji, Ando Nozomi and Nishizaki Masato end up coming upon the scene of the murder of the Noguchi couple, because of a plan they had devised. Nishizaki is arrested at the scene and is given a 10-year prison term because of his voluntary confession. 10 years later, Takano Shigeru, a former police officer who has misgivings about the verdict of this case, starts to pursue the truth. He is convinced that it all began as a result of an incident caused by Nozomi and Naruse on an island in the Seto Inland Sea on the summer 15 years ago. "They committed a crime at that time. It was for the sake of each N."