It's 1905 New York and Lily Bart (GILLIAN ANDERSON) is a strong but restrained, single woman in an era and upper crust society where women her age have already been long married or risk being considered old maids. That's not to say that she's lacking in suitors. Instead, none of them seem quite right to her.
She shares a mutual attraction with lawyer Lawrence Selden (ERIC STOLTZ), but he doesn't want to marry her. Wealthy businessman Sim Rosedale (ANTHONY LAPAGLIA) wants to do just that, but more for a business/societal arrangement than for love. Meanwhile, inventor Percy Gryce (PEARCE QUIGLEY) seems like a good catch, but Lily's efforts regarding him are constantly thwarted by Bertha Dorset (LAURA LINNEY), a married woman with a reputation for delighting in making people miserable.
Her conservative husband, George (TERRY KENNEY), seems interested in Lily, especially due to Bertha's flirtatious and possibly adulterous ways with other men, but can't bring himself to divorce her. As such, Lily lives with her Aunt Julia (ELEANOR BRON) and cousin Grace Stepney (JODHI MAY), attending her inner circle's many events with acquaintances Gus (DAN AYKROYD) and Judy Trenor (PENNY DOWNIE), and confiding in her friend, Carry Fisher (ELIZABETH McGOVERN).
Since Lily has something of a gambling debt and only gets an occasional allowance from her aunt, Gus decides to help her make some money through investments, although his intentions aren't purely financial. As word gets out about the two of them being seen together, coupled with Bertha's veiled efforts to ruin her reputation, Lily suddenly finds herself falling from her society's grace. From that point on, she tries to survive in any way she can.