Wang and his unconventional pedagogies successfully put Class 11-B under control. However, transfer student Ou Xian ming tips the balance. It’s later revealed that Xian Ming is the son of a criminal ringleader. It also exposes why Wang left law enforcement and Wu in the past. Wu realizes Wang quit the police job out of guilt after accidentally contributing to the death of his colleague. He decides to sneak into the mafia as an undercover agent to expose the perpetrator. Wu is determined to stand by his side, and Wang is deeply moved. Wang has sworn to protect the son of his late colleague. After Wang and Wu collaborate to identify the perpetrator, Wang also proposes to Wu. Will they have a happy marriage this time?