The story revolves around a mother, Yukie Kitazawa, and her two adopted daughters, Rumi and Tomoko. Yukie has a car accident while her husband is away on a business trip, and is forced to repay the other party, a young man named Taketo Nogawa, by sexual means. Taketo and his father, a powerful and corrupt business owner, blackmail and violate Yukie, Rumi and Tomoko. But Yukie's husband has been impotent for some time, and Yukie cannot help but welcome the sexual attention Taketo shows her. Taketo is portrayed as an impulsive, frustrated young man prone to occasional outbursts. Yumi, who works at Taketo's father's company, also joins in the emotional maelstrom; at times, she appears to be a loyal servant of the company and its interests, such as collecting the money owed by Yukie. At other times, she seems more concerned with the solidarity of the Kitazawa family. In the middle of it all stands Tomoko, the younger sister, a girl so innocent that she loves everyone. Tomoko does all in her power to keep the family happy and together despite their lack of genetic bonds. Ai Shimai does not strictly adhere to chronological order; it could be that the second and third parts depict separate, alternate endings. Also, some scenes are viewed through the eyes of different characters, a narrative technique that allows the advancing story to switch back and fill in where it previously left off. The series contains both heterosexual and lesbian love-making. Tomoko and Rumi even have sex while their mother and Yumi have sex on the bed, using a dildo.
Outside Japan
On July 22, 2011 Fakku, the largest English speakinghentai website in the United States, announced a partnership with Kitty Media that allows the website to stream DVD-quality episodes of Immoral Sisters season 1for free. Immoral Sisters was rumored to be aired in 2007 by Animax Brazil and Latin America. It would have been the first H anime to air in Animax. The news later confirmed by the popular Magazine Lazer in their issue #48 was later proclaimed as false by Animax officials in issue #52 of said magazine. Animax claimed that it had been just a rumor and that there were no plans to include hentai in their programming. The dub in United States featured porn starJenna Haze as the voice of Tomoko.
