Aya, who had been troubled by a long-standing sexless relationship with her husband, one day purchased an adult toy from an online shopping site. Later, out of curiosity, she tried to seduce a delivery man by showing him how she masturbates with the toy, but she was so excited that she accidentally leaked some urine, which the delivery man accidentally drank. Since then, she has felt a new excitement at the idea of "someone else drinking my urine." Thus, Aya's sexual preferences, which had opened the door to deeper perversion, progressed to the next stage...