Yamasaki Risako was leading a tranquil life with her 3-year-old daughter Ayaka and husband. One day, she gets a notification from the court of her selection as a juror candidate for a criminal case. The defendant of the case was Ando Mizuho, a full-time housewife and mother who is about the same age as Risako, who abused her 8-month-old daughter to death by dropping her into the bathtub. Risako is subsequently selected as the alternate juror.

As a fellow mother, Risako is disgusted with Mizuho who killed her own child. But after the trial begins, she gradually begins to superimpose the memories of her own past onto the situation of Ando Mizuho, the defendant herself. Risako eventually becomes troubled by the chaos and emotions that had lain dormant in her own heart.