田村西美（常盘贵子 饰）是一位普通的职员，一次意外中，她竟然无缘无故的被无良上司给解雇了，西美不仅丢了工作，就连工资也没能够领到，在这个节骨眼上，前不久才认识的行政代书荣田千春（深津绘里 饰）向西美伸出了援手，她灵活利用自己的法律知识，不仅帮西美讨回了拖欠的工资，更为她赢得了一笔数目可观的遣散费。
经历了这一事件，西美和千春成为了好友，目睹到人世间的种种不公，热血沸腾的千春决定绝不坐视不管，就这样，“正义代书战士”诞生了。替遭遇了不公的人们鸣不平，打击屈强凌弱的不正风气，怀抱着这样的坚定信念，西美和千春，在这两个性格迥异的女人之间，会发生怎样有趣的故事呢？

MPD Psycho (full title: Multiple Personality Detective Psycho – Kazuhiko Amamiya Returns) is a six-part Japanese surrealist horror miniseries directed by Takashi Miike, based on Eiji Ōtsuka's manga series of the same name.

Homicide detective Yosuke Kobayashi saw his wife killed by serial killer Shinji Nishizono. From the shock of the incident, he suffers from multiple personality disorder and becomes Kazuhiko Amamiya. Soon after, he goes on the hunt for revenge.