Before Ni Xia was 17 years old, she always believed that Xu Ziheng was the only person of the opposite sex in the world who could give her a feeling of protection, except for her father. In the four years after she turned 17, Ni Xia realized that only she could best protect herself, so she went to the police academy. Later, Ni Xia discovered that there was someone who could make her feel at ease.