Fresh Out of Prison, I Opened the Door and Landed in the Republican Era as a Secret Agent

Zhang Danfeng, an excellent student, suddenly becomes obsessed with gangsters and their code of brotherhood. At the crucial moment before his high school entrance exams, he goes astray. Despite trying his best, he squanders grades that could have gotten him into Peking or Tsinghua University and ends up at a junior college instead. After graduating, he can't find a decent job and continues hanging around with his old worthless friends. He winds up in prison for eight years before finally coming to his senses. But when he's released, he discovers that his parents have endured endless criticism from the villagers because of him, and eventually died of grief. Returning home, Zhang Danfeng opens the door to his room, only to find himself in the Republic of China era...