From Deux:
Sakura meets first Ryouichi at a male brothel and buys him for the night. As their supposed one night stand ends up becoming a somewhat stable monetary based relationship, feelings start to change. Can these two awkward people garner the courage to admit that their true feelings run deeper than merely sex and money?

Includes also:

• A Bird at Sea, A Door in the Sky: Ryuu is a sad but tough kid from Osaka who is trying to overcome his past. When an American, Stefan, takes an interest in him, will it lead to more than just friendship? Part of Rules / Hydra Series