Xiaomi is a cleaner who works in a budget hotel with Lily, who works at the front desk, and who is always seeking help from Xiaomi. One night, Lily persuades Xiaomi to cover her at the front desk for one night so that she can slip out to meet her boyfriend. A senior local official, Liu, brings two young girls, Xiaowen and Xiaoxin, with him to the hotel. Xiaomi immediately becomes suspicious. She observes the hotel’s surveillance system and starts recording it on her cell phone.

Early the next morning, two young girls look depressed. Their teacher senses something amiss and calls their parents and the police. An examination at the hospital confirms that both of them have been sexually assaulted. The police, led by the detective Captain Wang, searches the hotel and finds surveillance video that could convict President Liu, but the footage showing him entering the rooms of the two girls has been deleted. The police questions Lily, who claims to be on duty that night. Fearing that she would lose her job for covering for Lily, Xiaomi keeps mum and says nothing about the evidence she has.

Due to the lack of evidence, it seems like the local senior official is about to go scot free. Ms. Yan Jie, the lawyer of the two girls, is unwilling to give up and instinctively thinks that Xiaomi is lying…