Blanche DuBois functions as the protagonist of A Streetcar Named Desire. The play begins and ends with, respectively, her arrival at the Kowalskis’ apartment and her departure from it. The plot fundamentally traces the effects of her living with them; excepting the birth of the Kowalski baby, all the action and the other characters’ behavior, revolves around Blanche or in response to her. Mitch’s attraction to Blanche causes him to try to change his life by proposing to her—the main plot development in the play. Also because of Blanche, tension develops between Stanley and Stella, setting into motion Stanley’s aggression towards Blanche and his efforts to get her out of their lives—the central conflict of the play. 

At the beginning of Streetcar, Blanche is skittish and exhausted, near collapse but able to register her surroundings clearly. As we gradually learn, she has come to the Kowalskis’ having been virtually forced out of her hometown, stripped of her living accommodations and her job. She arrives with no clear aim or plan for the future, just “to rest…to breathe quietly again.” In essence, Blanche is seeking stability and comfort. As such, she sets her sights on Mitch, seeing him as a safe person. As this hope fades due to interference from Stanley, Blanche grows increasingly delusional. By the end of the play, she has retreated into a fantasy existence; while she reacts to actual sights and sounds, especially threatening ones, she seems not to recognize the people around her. The asylum doctor leads her away “as if she were blind.”

Although their lives will continue much as before, the other characters do not go untouched by their months-long brush with Blanche. As she departs, Mitch collapses and sobs, overwhelmed by the loss of another woman dear to him and the breakdown of his friendship with Stanley. A rift may have developed between Stanley and Stella as well. Although she allows him to comfort her, she feels consumed by guilt, wondering what she has done to Blanche.