Zi said: "I have five out of ten and am determined to learn, thirty and stand, forty and not confused, fifty and know the destiny of heaven, sixty and obedient, seventy and do what I want without exceeding the rules." Dong Tianming, who was supposed to settle down and stabilize at the age of forty, began to doubt his life due to changes again and again. Not only him, but also the friends of a group of seven people also staged the joys and sorrows of ordinary people's families in the twilight because of the changes in their lives. At this age, there are old and young, birth, old age, sickness and death, career ups and downs, emotional crises, and human affection, which makes the straight waist of people of this age seem to be staggering. Through the group portrait, the career and family experiences of the seven students led by Dong Tianming are depicted, with multi-level career dimensions, multi-angle gender relations, and diverse family ecology, reflecting the difficulties and sadness of life at the age of 40 in this society. Forty is not confused, if you can not be confused, you can be transparent; If you can be transparent and indifferent, it is good. Forty is not confused, if you can see through it, there is a way in the family business; The career is promising, the friendship is stubborn, and forty is good.