Rotten Business

Rotten Business is an optional side quest in Deus Ex: Human Revolution. It is given to the player by Mei.

Introduction
Mei, one of the more senior prostitutes working at the Heng Hua Hotel, has a problem: one of her friends and coworkers, another prostitute named Ning, has gone missing. Mei suspects foul play - augmented prostitutes bring in more business than normal ones, and under the iron fist of Diamond Chan, the new Heng Sha underworld kingpin, girls have been undergoing augmentation by force. Mei needs help finding Ning and dealing with Chan.

Overview
Jensen must find a prostitute named Ning that has gone missing. Mei suspects foul play. After finding her, Mei needs Jensen to find Diamond Chan and put an end to his reign once and for all. She needs him out of the picture permanently, which means either his death or a conviction - either method requires Jensen going to his apartment and dealing with him.

Ning
Mei suggests talking with a low-ranking gangster nearby named Chuanli, who might have information on Ning's whereabouts. This Chuanli is located on the roof of the Heng Hua Hotel and must be either bribed or persuaded to give up what he knows - that Ning is located in a side street near the Daigong district.

Upon reaching the lot, Jensen finds that Ning has three armed guards that must be taken out. After disposing of them, Jensen will find Ning in a locker, frightened but unharmed and unaugmented. Jensen should then report back to Mei.

Chan
After helping Ning, Mei turns her sights to Diamond Chan - as the new overboss of the Heng Sha underworld, he must be swiftly dealt with so that the prostitutes can go under new management. She needs him out of the picture permanently, which means either his death or an actual conviction. If Jensen opts to go for his conviction, Mei will give him an amount of drugs to plant in Chan's apartment. Either way, Jensen will need to go to Diamond Chan's 4th floor apartment in the Youzhao district.

Diamond Chan is alone and has no bodyguards, but he is armed. Jensen must take care not to kill him. Doing so will fail the quest. A melee takedown is ideal. After incapacitating Chan, Jensen needs to either assist in his 'suicide', or plant the drugs.

If the player wants to kill Chan and make it look like a suicide, Jensen needs to drag Chan's unconscious body to the outside roof and drop him, and he will die from the fall. If Chan is to be convicted, Jensen merely needs to plant the drugs in his coffee table and leave. Either way, Jensen can then report back to Mei for his reward.