"I can't compete with a dead woman."
Brenda, once the great love of Nate's life, is highly intelligent, highly protective of her emotions and highly skeptical of the possibility of being happy. She comes by her misgivings honestly: at the age of six she was declared a genius and placed in the care of psychiatrists who manipulated and scrutinized her every move. To make matters worse, her hell wasn't even a private one - it became the subject of a best-selling book titled, "Charlotte Light and Dark."
In addition, Brenda's family life is dysfunctional in the extreme. Her relationship with her parents (her father is recently deceased), both psychiatrists, has always been openly antagonistic. And while she loves and is protective of her brother, Billy, he's a manic-depressive who used to have the habit of going off his medication. The last time Billy quit taking his meds, he became dangerously violent and Brenda had to have him committed.
The one thing in Brenda's life that brought her happiness was her relationship with Nate, and yet she compulsively sabotaged it. She asked Nate to marry her, then engaged in anonymous sex - with individual men, a pair of twenty-something stoners, a husband and wife at a swingers party - behind his back. When he discovered her "secret life," Nate broke off their engagement, devastating Brenda and driving her to do something she vowed she never would: seek psychiatric help. She attended a support group for sexual addicts and later confessed to Nate that her behavior was motivated by "...the fear, of feeling...something real."
The experience inspires her to return to school to become a licensed therapist, a decision that pleases her self-involved mother. On steadier footing, she starts a relationship with Joe, the introspective musician who lives next door, and the relationship moves quickly, with talk of moving in together and even having children. When Nate appears, lost and still grieving Lisa's death, Brenda offers consolation, which inevitably leads to a rekindling. Eventually recognizing her old patterns, balking at commitment, Brenda ends the affair and confesses her infidelity to Joe. He reluctantly forgives her, until he catches Brenda and Nate in a compromising embrace. This time, Brenda has forced another ending. She runs straight back to Nate and, in a rare departure, impulsively tells him she loves him. Taken aback, he pulls away from her. But a series of traumatic events leads Nate to realize he's ready to build a future with Brenda.