On a stormy night in March 1980, a distraught Jean Harris arrives at the baronial Purchase, New York home of Herman Tarnower following a five-hour drive from McLean, Virginia.

The film then follows divergent paths, using flashbacks and flashforwards to tell the story of the couple's initial meeting, their evolving and eventually faltering relationship, the night of the shooting, and Jean's consequent trial for murder.

As time passes, she presses him to set a wedding date, until he finally confesses he has changed his mind about marrying her, primarily because he has no interest in playing the role of father to her sons.

Jean attempts to return the ring, but he insists she keep it, and, instead of allowing her to make a clean break from the relationship, he continues to manipulate her by taking advantage of her need for a dominant presence in her life.

Her staunch refusal to allow attorney Joel Aurnou to portray her former lover in a bad light prevents him from presenting any details that would support a defense of extreme emotional disturbance.

Playwright and screenwriter Phyllis Nagy made her directorial debut on Mrs. Harris after executive producer Elizabeth Karlsen asked her who she thought should direct her screenplay.

Nagy told Creative Screenwriting, "After I finished the first draft of that script, and Liz Karlsen brought me in to talk about directors, I knew she was going to ask me who I thought could direct this.

Her performance, which consists of two lines of dialogue totaling 38 words and lasts 14 seconds, was nominated for an Emmy Award for Outstanding Supporting Actress in a Miniseries or Movie.