'Riko' was taking care of her father-in-law 'Shigeji' with her husband's family. Shigeru, who had been relying on "urinary incontinence therapy", eventually became unable to excrete freely and collapsed in shock. Riko, who witnessed such a sad state of Shigeru, decided to offer her own urine, but she had no way of knowing that this would lead to a forbidden relationship between the two of them.
