Blanche DuBois arrives, penniless, in New Orleans to stay with her sister Stella and her brother-in-law Stanley Kowalski. A former schoolteacher from a wealthy family, she has been evicted from her family home, Belle Reve, after the deaths of several family members wiped out her and Stella's inheritance. It is also later revealed that, years earlier, her husband, Allan Grey, committed suicide after she caught him having sex with another man. She had a series of meaningless affairs to numb her grief, and was soon thrown out of her hometown of Laurel, Mississippi, as a "woman of loose morals" after sleeping with a 17-year-old boy. Behind her veneer of social snobbery and sexual propriety, Blanche is deeply insecure, an aging Southern belle who lives in a state of perpetual panic about her fading beauty. Her manner is dainty and frail, and she sports a wardrobe of showy but tattered evening clothes, as indicated in the stage directions for Scene 10: "She had decked herself out in a somewhat soiled and crumpled white satin evening gown and a pair of scuffed silver slippers with brilliants set in their heels."
From the start, Blanche is appalled by her sister's poor living quarters and the coarseness of her brother-in-law. She calls Stanley an ape, and shames Stella for marrying a man so violent and animalistic. Blanche is not shy about expressing her contempt for Stanley and the life he has given her sister, which makes him proud. For his part, Stanley resents Blanche's superior attitude, and is convinced that she has squandered Stella's portion of the money from the sisters' ancestral home. Blanche begins dating Stanley's friend Harold "Mitch" Mitchell, who is distinct from Stanley in his courtesy and propriety, and sees in him a chance for happiness. That hope is destroyed, however, when Stanley learns of Blanche's past from a traveling salesmanwho knew her, and reveals it to Mitch, who ends the relationship. Blanche begins drinking heavily and escapes into a fantasy world, conjuring up the notion that an old flame, a millionaire named Shep Huntleigh, is imminently planning to take her away. The night Stella goes into labor, Stanley and Blanche are left alone in the apartment, and Stanley, drunk and powerful, rapes her. This event, coupled with the fact that Stella does not believe her, sends Blanche over the edge into a nervous breakdown. In the final scene, Blanche is led off to a mental hospital by a matron and a kind-hearted doctor. After a brief struggle, Blanche smilingly acquiesces as she loses all contact with reality, addressing the doctor with the most famous line in the play: "Whoever you are...I have always depended on the kindness of strangers."