Xia Zhiyao, a 19-year-old college girl from Huaguo, is sent by her uncle, an Interpol insider, to stay beside Shen Yu and gather intelligence. As they live together, Shen Yu gradually falls for her and sacrifices much for her, even letting her go back home. After returning, she gets the news that Shen Yu has been detained. In the interrogation chamber, Shen Yu at last learns the truth about her secret task.