Mato No Hoshikuzu summary:

A scamming soldier vs. a secretly gay gangster in old Shanghai as part of this noir yaoi story! Shoulai Kang is a lieutenant in the mobile infantry and he manages to confiscate a major load of opium belonging to the mafia group that controls Shanghai. Kang, who has high aspirations for moving up the ranks, keeps his finding a secret and then goes to meet the mafia boss who the opium belongs to, Yuron Wang. Then, when he figures out that Yuron can't sleep with women, he get the idea to use his sweet charms to get some special favors out of Yuron...