Song Chen, a former bad boy, was influenced by his mentor and decided to become a teacher to change the fate of more bottom-ranked students. When he returned to school for internship, he was assigned to the top class 1 and became the head teacher of the top students. Tan Shutong, the daughter of the mentor and a hot-tempered top student, was full of resistance to the teaching profession, but because of a failed job search, she had no choice but to return to high school and became the head teacher of the last-place class 18. Rookie teachers vs. students who don't want to change, the two groups of people who look down on each other are forced to get along day and night. After the confrontation, their prejudices against each other are also quietly disintegrating... At the same time, Song Chen's old classmates, the previous generation of class 18, also entered the society at this time. They rented together and became the dog-headed military advisors of the two rookie teachers. Although they are adults in the post-adolescent period, they also face similar troubles as middle school students. The stories of a room full of "post-95" social rookies and the new "post-05" teenagers are intertwined. Can he (she) become the ideal adults?