Experimental No. 3 Middle School is a private school where students from all over the country study. During the summer vacation, a group of poor students were arranged to make up for the lessons, but no one was willing to serve as substitute teachers. Under the leadership of the "copycat" discipline director, people from all walks of life with their own secrets were recruited to be their substitute teachers. As a result, strange things were rampant and farces continued. The students also understood many principles of life and work in the summer vacation full of laughter.