In the online drama "Detective Chinatown," Ivy(Qin Feng) and Wen Song (Hao Ran) were good friends and colleagues who worked together as detectives. Ivy had once been prejudiced against Lin Mo because of his past, but he gradually put down his prejudice and recognized Lin Mo's help and trust in him. In the movie, the reason why Ivy did not kill Lin Mo and got rid of Wen Song was that he believed that Wen Song's actions were beyond his control and involved his own and the company's interests. Wen Song was related to illegal immigration and money laundering. Ivy was worried that Wen Song's actions would threaten the safety and interests of himself and the company. Therefore, he chose to get rid of Wen Song to stop him from committing further crimes. It should be noted that this was only the plot of the online drama Detective Chinatown. The specific plot and character relationships may vary from version to version.