Jessica Stein (Jennifer Westfeldt) is a sensitive, but neurotic, New York journalist who is at the end of her emotional rope. Her brother Dan (David Aaron Baker), is engaged. Her best friend and co-worker Joan (Jackie Hoffman) is pregnant. On top of that, Jessica hasn't dated in a year, and she can't sleep. After an optimistic but nightmarish dating spree, which is set up by her overbearing and meddlesome mother Judy (Tovah Feldshuh), Jessica decides she needs a change in her life.
Helen Cooper (Heather Juergensen) is a fairly successful art gallery manager who is fed up with having quicky sex with various men, including her delivery guy, in various times and places. Confused about her sexual orintation, as if she thinks she may be a lesbian in denial, Helen puts a personal ad in a local newspaper asking for a date with someone. The following day, Jessica happens upon to read intriguing personal ad, whose only drawback is that it's in the women seeking women section. On a daring whim, Jessica decides to answer it. She meets the hipster Helen at a local bar for drinks and, to her surprise, they click instantly. After going for a evening of banter, connection and heated debate about Jessica's personal life and her repression for happiness, the discussion culminates in a kiss that Helen gives which confounds and intrigues even the reluctant Jessica.
Over the next few weeks, the two women proceed to muddle through an earnest, but hilarious courtship, making up the rules as they go along with private make-out sessions to casual dates to the local cinema. Jessica doesn't really know how to think through this new situation. Meanwhile, everyone at Jessica's office notice that she is walking on cloud nine and is very happy. Josh Myers (Scott Cohen), her boss (whom she dated for a while in college) also notices and starts to feel strange that hes not a part of this new, happier Jessica.
On another dinner date, Jessica and Helen go out, they nearly get picked up by two sleazy guys at a local bar, and then proceed to return to Helen's apartment for another make-out session, which gets intrupted by one of Helen's boyfriends. Helen asks him to leave, but after he does so, Helen comes down with a mild cold which puts off her and Jessica's further make-out session.
One weekend, Jessica is invited to her mother's country house on Long Island and she, on a whim, takes Helen with her for emotional support to help her face off against her mother. Some other people also show up including Dan with his fiancee, as well as Josh who tries to persuade Jessica to give them another chance with whatever they used to have. But confused as ever, Jessica declines. She then proceeds to consumiate her romance with Helen that very night in her bedroom.
Some months later. A happy and improved Jessica flaunts her happiness in and out of the office, as her romance with Helen kicks into full swing. But Helen becomes more frustrated that Jessica wants to keep their romance a secret at any cost. One day, a very pregenant Jackie runs into Jessica and Helen while food shopping, and after catching Jessica in a lie about her and Helen, Jackie becomes prevy to Jessica's romance with Helen.
But the tension between Jessica and Helen over their closeted romance explodes one day, when Jessica is with her mother at a bridal store, trying out a dress for her brother's wedding. Helen passes by, sees Jessica in the dress and asks her what it's for. Her mother is surprised that Helen didnt know about the wedding and is even more surprised when Helen said she didnt get the invitation. Helen runs out of the store, Jessica follows and the two have an argument about it outside. Jessica refuses to bring Helen to the wedding with her as her date, and Helen gets upset and tells Jessica that its over between them.
At dinner that night at Jessica's parents house, Jessica starts getting very upset and leaves the dinner table. Her mother, Judy, follows her out and sees that Jessica is crying. Neither says very much... until Judy says, "Jessica, I think Helen is a very nice girl." Apparently, Judy has been aware from the very beginning about her daughter's romance with a woman. That very night, Jessica rushes to Helen's apartment and invites her to the wedding. Helen agrees and goes.
At the wedding, all of the grandmothers in attendance are asking Jessica and Helen about their relationship and are completely supportive... and even nosy. Jessica and Helen look happy. Josh is late to the wedding, so is still completely in the dark about the relationship. That night, Josh tells Jessica that he is still in love with her. She comes out to him and hes completely shocked.
A few months later. Jessica and Helen have moved in with each other, but their romance slowly slides into more of a platonic friendhsip. Apparently, that is not enough for Helen so she moves out. Jessica is crushed but gets over it.
Another few months later, a new and improved Jessica has settled in a new apartment, and has quit her journalist copywriting job. One day, Jessica runs into Josh, whom has also quit his job, in a book store and the two promise to meet up. The last scene of the movie is of Jessica meeting Helen for drinks, after Jessica had her "first date" with Josh.