Shen Xin didn't know about Shen Xi's plans, so she was always strongly opposed to him being with Fang Mengyao, especially after coming to the Beishi Base. Shen Xi went to work with Zhao Qiankun and entered the research institute, spending almost all his time inside and rarely coming out. Without him, Fang Mengyao became more and more unruly, dressing up flamboyantly and flirting with men all day long.
Although Shen Xin did not like Fang Mengyao, she always considered her as Shen Xi's woman. Fang Mengyao's actions clearly showed she was not taking Shen Xi seriously and wanted to make a fool of him. How could she tolerate that? Moreover, Fang Mengyao had the audacity to compete with her for Qiu Yiming!