China's five-thousand-year tradition has evolved from polygamy to today's monogamy. Coupled with the influence of patriarchal society, there have been wives and concubines with many husbands. In today's society, men and women living in metropolises are attracted to each other, and are tempted by all kinds of temptations. Enjoying your own happy life, but influenced by the law and social moral opinions, some emotions go underground, which is called "underground love". Such emotions cannot be seen in the light, and they are cautious in everything. They understand the general principles, but many people touch the restricted area of emotions like "moths flying into the flame".