Risako Yamazaki (Kou Shibasaki) lives with her 3-year-old daughter and husband. She is informed that is selected as an alternate lay judge in a criminal case. The defendant in the case is Mizuho Ando. She is also a housewife and about the same age as Risako Yamazaki. She is on trial for drowning her 8-month-old daughter in a bathtub. Risako Yamazaki feels hatred to Mizuho Ando, but, after the trial begins, Mizuho Ando’s situation reminds Risako Yamazaki of her own past memories.