Allison "Allie" Jones (Bridget Fonda) is a software designer in New York City, engaged to Sam Rawson (Steven Weber (actor)). Sam's ex-wife calls, and it is revealed that he slept with her recently. A hurt and angry Allie throws Sam out, breaking off their engagement, and is comforted by neighbor Graham Knox (Peter Friedman), an aspiring actor. The next morning she attends a business lunch with Mitchell Myerson (Stephen Tobolowsky), a fashion house owner who is looking to buy Allie's revolutionary new program. He manipulates her into significantly reducing the cost; as he is her first and only client, she accepts.
In New York, PR colleagues and roommates Holly Parker (Kristen Miller) and Jan Lambert (Brooke Burns) are disputing a promotion in their agency. The unethical Jan deceives Holly and sends her to Chicago. Meanwhile, she seduces Holly's boyfriend David Kray (Tad Babcock), in the opening of a fancy restaurant he owns, and they have a one-night stand. When Holly arrives back home, she finds out David cheated on her with Jan, and decides to move into a new apartment. She schedules a meeting with the needy Tess Kositch (Allison Lange) and they become roommates and friends. When Tess cuts and dyes her hair identical to Holly's, she sees that her new roommate is obsessed with her. When Holly follows Tess to an underground nightclub called "Sin", she realizes that the girl is deranged. But Tess wants to be her friend and put Holly out of her misery by eliminating her former bad friends.
