College student Joseph last name changed to protect the innocent plans on spending a hot and hazy summer with his girlfriend Cynthia Glass. He quickly settles in to Cynthia's family home - though not her bedroom, to appease her grandmother - where a very warm and friendly welcome awaited him. Signed on to work at a kids' camp during the day, Joseph fully intends to spend his evenings sneaking across the hall for a vigorous round of mattress aerobics - at least, that's when he's not worrying about his incomplete end of term paper (he and Cyn have been participating in too much physical, and not enough mental exercise recently). Meanwhile, Cynthia's mother ('just call me Mimi') is busy making props for a festival of operas...which is how she comes to be constructing a golem in the basement. (Think big Jewish robot made of clay, brought to life through magic to carry out his creator's bidding - very handy in emergencies.) And this summer, it just so happens that there is an emergency - as Joseph gradually uncovers the truth about the Glass household, where nothing's as transparent as it first seemed.
There are saucy secrets afoot and the incredibly close-knit family is about to be shattered...