Sex and love — can the twain ever meet? In the world of fūzoku, a euphemism for Japan's enormous sex industry, that question is usually answered in the negative.

In the industry's lower reaches, sex is regarded as a service to be offered in defined ways for specified times, something like a 30-minute foot massage, with about the same level of emotional exchange. In its upper reaches, where expensively gowned young women cater to the whims of well-off men, love is suggested and even promised, but the adage "no money, no honey" still applies.

Daisuke Miura's new film of his own award-winning 2005 play "Ai no Uzu (Love's Whirlpool)" offers up a 1970s swingers' twist on the ancient fūzoku business model. At a split-level flat on a backstreet of Roppongi, Tokyo, men pay ¥20,000, women ¥1,000 and couples ¥5,000 apiece to spend the hours of midnight to 5 a.m. at a sex party. Presiding over this orgy are a jaded manager (Tetsushi Tanaka) and bartender (Yosuke Kubozuka) who explain and enforce three simple rules: Take showers prior to sex, use protection and respect the wishes of the women.