Three years have passed since he retired from teaching. His father-in-law, Ryutaro, was living happily with his son and his wife. One sleepless night, he heard the seductive voice of his son's wife from the other side of the door and ended up peeking in on her masturbating. When An noticed this, she began to see her father-in-law as a sexual object, as she had not had sex for over three years due to her husband's infidelity. What will happen to their relationship? Will he be able to resist the temptation of An, who exudes a ripe sexiness...?