CP is Zhao Siqing and Xin Yue OTL
But why do I want to pair up Zhao Siqing and Zhou Yu so much! You see, the names all match so well -v-
Basically, this is the story of the principal's daughter of a certain school having an affair with a teacher. She was irresponsible and came back many, many years later. She didn't know whether she was responsible or not... In the end, she was responsible for the happy ending of the two people and then had endless happy time.