Himitsu (秘密, Secret?), is a novel by Keigo Higashino, published in English as Naoko by Vertical. The story centers on a man whose wife and daughter are in a terrible accident; the wife dies, but when the daughter wakes up, he discovers his wife's mind inside.
It was made into a 1999 Japanese film, directed by Yōjirō Takita. In the 2000 Catalonian International Film Festival it won awards for Best Actress (Ryōko Hirosue) and Best Screenplay (Hiroshi Saitô) and was nominated for Best Film.
The 2007 film The Secret is based on the Japanese film.
Read more about Himitsu: Synopsis