寂寥无声的凝视

剧情：

Yan Xin is an ordinary white-collar worker. He really likes to have sex with different guys. Yun Fei is a stalker, following, taking pictures and spying on others' privacy is his biggest hobby. From time to time, Yun Fei became curious about Yan Xin and started to follow him. During a date, Yan Xin met a pervert and his life is in danger. After witnessing everything, what should Yun Fei do?