Driving home late at night, Motomura Hiroshi accidentally hits a young woman with his car. He panics and flees the scene for home where he confesses to his wife Yoko, signaling his desire to turn himself In. Yoko, however, convinces him that his arrest would mean the end for their already damaged family.
Their daughter Azusa is having an affair with a married man, the son Rikuo, the victim of bullying at school, refuses to go to class, and the senile grandfather is getting harder to manage. Yoko urges the family to move the car into the living room and there take it apart and destroy the evidence. Her plans at first seem to backfire when Azusa, blaming her father and seeing no point in rescuing the family, decides to leave home.
Hiroshi himself, still racked with guilt, attends the funeral of the victim and almost confesses. But Yoko’s hard work and determination soon begins to change the family. Azusa returns home when the wife of her lover discovers their affair and Rikuo begins attending school again. Ironically, this return to normalcy only further sparks the suspicions of their snoopy neighbor, who is convinced that the family has murdered the grandfather.
Hiroshi, unable to bear the guilt, finally turns in his resignation at work and heads for the police
station. To his amazement, he learns that another man has been arrested for the crime. Hiroshi, apparently only stunned the woman with his car; she was killed later by another car after she got up. He returns home with the good news only to discover that his family has captured the Intruding neighbor and are contemplating getting rid of her. In the struggle, the house is set on fire, trapping Yoko and the grandfather.
The two mount all that remains of the car, the chassis, and use it to make a getaway, taking the family with them. Repairing the car with parts found at a Junk yard, the Motomuras head out on the road.

Following In the footsteps of Morita Yoshimitsu’s Family Game (Kazoku gemu, 1983) and Ishii Sogo’s Crazy Family (Gyakujunsha kazoku, 1984), The Family Secret uses black humor to cast a sharp, satirical eye at the modern Japanese family. Suffering various-contemporary Ills, the family can only be saved through covering up a crime and becomes normal only when it totally escapes the reality of Japanese life. The Irony is doubled by Mizutani Toshiyuki’s skillful editing and camera movements, which constantly equate the family with the car .they so furiously try to destroy. Like many other recent Japanese directors, Mizutani learned his craft making soft core porn films.
Color / Vistavision / 1992 / 100 min / Kitty Film, Suntory
Director :                                Mizutani Toshiyuki
Script :                                    Mizutani Toshiyuki
Sunamoto Ryo
Photography :                        Nagata Yuichi
Art Director :                          Oikawa Hajime
Music :                                  Sahara Kazuya
Producer :                             Ijichi Kei
Planning :                             Mukugi Hironao

Motomura Hiroshi :              Nagatsuka Kyozo
Yoko, his wife :                    Nakao Mie
Azusa, his daughter  :         Chiharu
Rikuo, his son :                   Hashimoto Mitsunari
Giichiro, his father :             Nakaya Noboru
Harasawa Sada, a neighbor: Oshima Yoko
Zenji, her husband:             Iwamatsu Ryo
Kamijo Takayoshi, Azusa’s lover: Otaka Hiroo
Yumiko, his wife :                Ishii Naeko
Setting: A Japanese dry in the early 1990s.