1999 Shanghai1999 年七の月～上海; 1999 Nen No Shichigatsu; 1999-nen Shichi no Gatsu - Shanghai; 1999nen 7 no Tsuki Shanghai; The Seventh Month in 1999 - Shanghai

From Beautiful-Soup: "1999" is an angsty and widely varied series about a bunch of teenagers. One of them is the son of a drug lord and so as you can imagine, all sorts of shit goes down, surrounded by a backdrop of convoluted and fluctuating interpersonal relationships. This a plot heavy manga with some mildly-explicit sexual activity.