Sano Bungo (Suzuki Ryohei) was found guilty of serial murder by poison that occurred 31 years ago and was sentenced to death. His family has been living a hard life as the murderer's family. However, when his son, Shin (Takeuchi Ryoma), is transported back in time to the period immediately prior to the murder, the parents he encounters are living in happiness and love. Believing in his father's innocence, Shin sets out to find the truth and becomes determined to change the past.