Half an hour later, as dinner is finishing up, the lights go out. Tom feigns ignorance of the cause. Amanda, unfazed, continues to be as charming as she can. She lights candles and asks Jim to check the fuse box. After Jim tells her that the fuse box looks fine, Amanda suggests that he go spend time with Laura in the living room.
As Amanda and Tom do dishes in the kitchen, Laura warms up to Jim, who is charming enough to put her ease. She reminds him that they knew each other in high school, and that he used to call her "Blue Roses." Jim feels ashamed that he did not recognize her at once. They reminisce about the class they had together, a singing class to which Laura, because of her leg, was always late. She always felt that the brace on her leg made a clumping sound "like thunder," but Jim insists that he never noticed it.
They have a friendly conversation by candlelight. Jim reveals that he was never engaged, and that his old girlfriend was the one who put the announcement in the yearbook. They no longer see each other. Laura speaks admirably of Jim's voice, and he autographs the program of the show he was in, The Pirates of Penzance. Indeed, she was too shy to bring the program to him back in high school, but she has kept it all these years. Jim tries to give Laura advice about raising her self-esteem, and talks about his plans to get involved with the nascent television industry. He speaks of the numerous courses he is taking, and his interest in programmatic methods for self-improvement. He calls money and power the cycle on which democracy is built.
Laura shows Jim her glass collection. They look closely at a little glass unicorn, remarking on how the unicorn must feel odd due to its uniqueness. They put the unicorn down on a different table, for "a change of scenery." Laura bashfully admires Jim, while Jim grows increasingly flirtatious. When he hears the music of the Paradise Dance Hall, he asks her to dance with him. He tries to help her shed her self-consciousness, and the two of them begin to grow close - but suddenly, they jostle the table and knock over the unicorn, breaking off its horn. Jim apologizes but Laura tells him not to worry. She can pretend the unicorn had an operation to make it feel less freakish.
Jim speaks admiringly of Laura's character, and then begins to praise her looks. He tells her that she is pretty, and Laura blushes with shy bliss over this unexpected praise. Then, suddenly, Jim kisses her. Immediately, he seems to regret the kiss. Awkwardly, he admits to Laura that he is engaged. Laura's face reveals terrible desolation. She gives him the broken unicorn as a souvenir. Then she goes to the Victrola and winds it up. Amanda rushes in, only to hear Jim's announcement that he has to leave. When Amanda tells Jim that he should come again, he tells her about his plans to marry his current girlfriend. He also mentions that no one at the warehouse knows about the engagement. He leaves.
Amanda, furious, calls in Tom. She accuses Tom of playing a practical joke on them, by intentionally bringing in another woman's fiancé to disgrace them. She is visibly shaken; the evening has been expensive for the Wingfields, and her dreams for her daughter have been shattered. Angered by her accusations and not willing to put up with her foolishness, Tom tells her that he is going to the movies. She accuses him of selfishness, and says that he never thinks of them, "a mother deserted, an unmarried sister who's crippled and has no job." Infuriated, Tom leaves.
Tom, as narrator, then addresses the audience from the fire escape, telling us that soon after that night he went down the fire escape one last time and left St. Louis forever. As he gives this final speech, Amanda and Laura are visible through a transparent fourth wall that drops down into place in front of them. This closing speech is one of the most famous moments in all of Williams' work, and indeed one of the most haunting and beautiful moments in all of American theatre. He talks about time being the "longest distance between two places," and his long search to find something that he himself seems unable to name. He tells the audience that for all of the years since he left, he has been pursued by the memory of Laura. Though he tried to leave his family behind, his memory of his mother and sister continues to haunt him. He finishes by imploring his memory of Laura to blow out her candles, "for nowadays the world is lit by lightning." He says goodbye, although in the script it is unclear whether he is bidding goodbye to the audience or to his sister. Behind him, visible through the transparent wall, Amanda comforts Laura silently throughout Tom's speech. When Tom has finished speaking, Laura blows the candles out, ending the play.
Although a great deal depends on the actor's interpretation, Jim's enthusiasm is selfish and empty-headed. He shamelessly leads Laura on, not maliciously but also without any careful consideration. He enjoys her company because, like Tom, Laura remembers his glory days. His speeches praising self-improvement and night classes are symptomatic of the most unimaginative and vapid interpretation of the American dream - culminating in his appalling praise of the lust for money and power as the cycle on which democracy is built. As Tom said in the opening of the play, Jim is more a part of the real world than anyone in the Wingfield family. He is fully a creature of the world and worldly pursuits. He knows what no one else does - that he is engaged - and he still gives Laura the kiss that raises her hopes before he tells her the truth.
Their different memories of school reveal how fatally self-conscious Laura is. The sound of her brace mortified her back in high school, but Jim cannot remember it at all. Jim tries to convince Laura that she is worthwhile and unique. A more gracious interpretation of his character would argue that part of his motivation is a desire for Laura to see how beautiful she is.
The glass unicorn, of course, is a clear symbol for Laura. She, like the unicorn, is odd and unique. Both Laura and the unicorn are fragile -and Jim "breaks" both of them. Laura's subsequent gift of the broken unicorn, however, suggests the extent of her affection for him. For Jim, the evening has been insignificant. But Laura has harbored a girlish crush on him for many years - she even saved the program of the play in which he starred - and the gift of the unicorn, an item that is a symbol of herself, shows how much she still likes him. It is the gift of an odd and painfully shy girl, for whom kissing Jim (probably her first kiss) was a climactic experience. For a brief moment, the Wingfield apartment was a place of dreams. Amanda experienced a return to her girlhood, Laura showed her long lost love her precious glass menagerie, and the place was full of the music from Paradise Dance Hall. But the unicorn breaks, the music of "Paradise" gives way to the sad sounds of the Victrola, and even Amanda is left without defenses against reality. For the first time, she refers to Laura as "crippled," breaking her own rule, and she seems to acknowledge that Tom will soon leave them.
This scene has its share of rose imagery. The new floor lamp has a rose-colored shade; Laura herself is "Blue Roses." The rose-colored light makes Laura look beautiful; she is bathed in rose-colored light, she is "Blue Roses," and she is also, in many ways, the surrogate for Williams' sister - whose name was Rose. Williams uses the rose as a motif for Laura to emphasize her delicateness and her beauty, as well as her worth. The fantastic blue color of the flower shows, however, that Laura is not a being of this world. Laura's association with a candle in the final moment stands in sharp contrast to a world "lit by lightning." The image of lightning suggests a hostile and overpowering world, and in the last scene a storm is brewing outside. Especially as a lone figure juxtaposed to the turmoil of the forties and the war to come, Laura seems hopelessly frail and vulnerable.
Tom's closing speech, of course, is a peerless and infamous moment. The descending fourth wall puts a powerful but permeable barrier between Tom and his family. They are behind him, behind him in time and in the physical space of the stage. And yet, Tom cannot seem to shake the memory of them, and they are clearly visible to the audience. Although he has never explicitly spoken of one of the play's most important themes - the conflict between responsibility and the need to live his own life - it is clear that he has not been able to shake the guilt from the decision that he made. The cost of escape has been the burden of memory. For Tom and the audience, it is difficult to forget the final image of frail Laura, illuminated by candlelight on a darkened stage, while the world outside of the apartment faces the beginnings of a great storm.