Masaki Shibata Sinichi is a theater actor who murders a man and his wife. Masaki confesses the crime and alleges that the reason for it was that the woman, five months pregnant, had criticized her show. It could be a very simple case to settle if it were not for the "mitigating liability" contemplated in the criminal system of Japan. Masaki must undergo a psychological test to determine his sanity. 《刑法第三十九条》电影剧本。【【心中的法】】。悶騷的電影，有病的人。。Justice in one's own hands。 日本刑法第三十九条：心神丧失人的行为，不罚。心神耗弱人的行为，得减轻其刑。 畑田修夫妇惨遭杀害，嫌疑犯柴田正树（堤真一 饰）承认杀人事实，但否认动机。柴田的反常举动引起法庭注意，经司法鉴定认为其患有精神分裂症，按刑法第三十九条无需承担法律责任。 担当鉴定助手的小川香深（铃木京香 饰）则认为案件存在疑点。经过进一步调查，小川得知被害人畑田修15岁时曾杀害一名女童，后因未成年保护条例及刑法第三十九条躲过制裁。小川就此入手，发现女童还有一个哥哥，他与这起案件又有什么关系呢？
