Rule No. 1 is a drama comedy about 'fish-out-of-water' Caroline and her sister Sarah, both in their mid-twenties. As Caroline is forced to leave her unfaithful boyfriend, the only place she can crash is her sisters' whom she does not have a good relationship with. Sarah graciously offers Caroline a tiny room in her apartment and decides to help her find Mr. Right. Caroline isn't sure she's cut out for the dating game, but Sarah assures her there's nothing to it. This takes Caroline on a series of grueling and comic dates, with everything from nimble pickup artists, to adventure sports freaks and a karaoke-singing stockbroker. But what the two sisters really find in the end is themselves.
