She is first seen in a flashback where she tells Paul that she is disappointed that he killed off Misery Chastain, because Misery was a very profitable character. She cites that the Misery novels paid for his daughter's braces, her college tuition, and his houses. Paul however is bored with the character and felt his career would go nowhere if he continued with her. He tells Marcia that he never meant for Misery to become his "life" and if he had not killed her off now, he would have ended up writing her forever. He also feels that he has not been a real writer since he "got in the Misery business".
She is then seen phoning the Colorado police nearby where Paul Sheldon was staying, in Boulder.
She is last seen in a New York City restauraunt with Paul, discussing the release of his latest (and first post-Misery) novel, The Higher Education of J. Philip Stone. She tells him that the New York Times review will be a "love letter", and that in addition to other positive reviews he has a chance at winning some prizes.
She is surprised he isn't very thrilled upon hearing the news. He tells her he wrote it for him. She asks him if he is interested in writing a nonfiction book about his ordeal at the hands of Annie Wilkes, but he declines as he says it is worst horror of his life.