This story is from Strange Tales from a Chinese Studio.
An elderly man named Feng had a son, Xiangru, who studied diligently but repeatedly failed the imperial examinations. One night, while reading in the courtyard, Xiangru was astonished to see a beautiful girl named Hongyu gazing at him affectionately from atop the wall. He invited her down, and they soon fell in love, meeting secretly every night.
One evening, Feng discovered Hongyu at his son's door and severely scolded Xiangru. Hongyu slipped away and never returned. Later, Xiangru married a woman named Wei, and they had a son named Lucky.
Tragedy struck when a local bully named Song, captivated by Wei's beauty, abducted her. Feng was so indignant that he soon died. One day, a stranger confronted Xiangru, reminding him of his father's death and wife's abduction. Xiangru confessed his desire for revenge but felt powerless. That very night, Song was beheaded.
The county magistrate suspected Xiangru and had him arrested. On the night of the arrest, as the official lay down, a dagger was found stabbed into his headboard.
Later, at home, Xiangru heard his son talking outside. He opened the door and was overjoyed to find Hongyu standing there with Lucky. She smiled and explained, "I am no ordinary girl but a fox spirit. Knowing you were in trouble, I have been protecting you in secret." From then on, Hongyu stayed with Xiangru, managing the household and teaching his child.