A low-key private detective agency in Paris is run by Rie and her lover and partner Kishin, two ex-pats who tick along between cases by giving guided tours of the city to busloads of Japanese tourists. After the wealthy Okuyama hires them to trail his French mistress Lorraine whom he believes to be having an affair, feeble-willed Kishin finds himself seduced by this femme fatale and way out of his depth in a seamy underworld of rich Japanese businessmen, S&M games and huge piles of money.