From what I can remember, you move into a house with a family who are all undercover for the dads job as a cop, and he is trying to infiltrate a gang and needs you to play a role. The basement is off limits until you are more involved with the gang and then you find out its being used as a sex dungeon of sorts. You also get to have sex with the wife eventually, all under the guise of keeping your cover. And I think the gang was involved in making some kind of sex drug as well.