Young woman goes to a party that is known for sexual hookups. She decides she doesn't want to know who her lover is. So she has her friend send a guy into the room she's in. The lights are off and there is no talking, at least none from him. It's the best sex in her life and as time goes by she becomes more obsessed with the sex and finding out who had given her the best sex she's had. So she has her friend set up a meeting with the guy. She is at first pissed off when she finds out that the guy she had sex with was her brother. Then she and her brother decide to give sex another shot to get it out of their system. They may end up living together as husband and wife and may have kids together. I think at one point the brother has sex with his sister's friend that set them up together. But I don't think that goes anywhere.