Emma and Adam (Natalie Portman and Ashton Kutcher), two friends with either no luck or no time for real relationships, engage in a purely physical relationship. The rules are simple: none of the gooey, lovey-dovey stuff that comes with being a couple, no jealousy, no lying...ultimately - keep their relationship strictly physical. But it's not long before things get complicated when they start to think they might want something more.