Returning to her bohemian apartment in San Francisco one day, 19-year-old Jill Tanner discovers her new neighbor staring at her through a window and later, through their shared paper-thin walls, hears him arguing with his mother. Free-spirited yet worldly-wise, Jill decides to invite herself into the man’s apartment. Jill’s neighbor, twenty-year-old aspiring songwriter Don Baker, explains that his loud phone conversations with Florence, his overprotective mother, are about a pact in which she has agreed to allow him to live on his own for two months without her interference. After Jill then candidly talks about her first marriage at sixteen, she concludes that in order to avoid hurting people she has foresworn any commitments. When Jill learns that Don is blind and thus not a Peeping Tom, she naively asks him if he has a sixth sense. Don explains that, like many blind people, he does have “shadow vision,” in which he can sense physical obstacles in front of him and thus avoid certain missteps. Moved by Don’s determination and lack of self-pity, Jill explains her rootless existence with a quote from Charles Dickens’ Bleak House in which a character begs to be as free as the butterflies. However, when Jill mistakenly names the author as Mark Twain, well-read Don corrects her and then sings of finding independence in his own song, “Butterflies Are Free.” Although Jill asks him awkward questions about whether he has “seen” things, the unflappable Don encourages her to have more confidence in her abilities. Taking a walk to a local boutique together, Don shows Jill how he negotiates the city by counting steps to each destination, while Jill talks about her upcoming audition with theater director Ralph Santore, who wants to marry her. At Jill’s suggestion, Ron buys a stylish new outfit, including a floral shirt, leather fringe vest and vintage French Legion hat, to enhance his hopes of success on the stage. Later at the apartment, Don talks about Florence’s children’s books in which young, blind superhero “Donnie Dark” performs amazing feats despite his disability. Although she wrote the books to encourage her son, Don remembers feeling only inadequate in the face of Florence’s grand expectations. With the help of his neighbor Linda, Don found the courage to move away from home, but was left heartbroken when Linda took a lover. Jill shares Don’s disappointment in love and suggests that they open the door between their apartments out of friendship. Attracted to Don, Jill offers to let him touch her face so that he might “see” her. Don is horrified when he accidentally pulls off Jill’s false eyelashes and her hairpiece, which she uses to enhance her flamboyant style. Unfazed, Jill guides Don’s hand to her breast, but as they kiss, Don pulls back, accusing Jill of patronizing him. Jill retorts that she does not have pity for any man who sleeps with her. The next morning, Jill tells Don that their lovemaking was like Christmas and Fourth of July combined and then shares the secrets of her keepsake box with him. Soon after, Don, recognizing the scent of his mother’s perfume, calls out to Florence, who has entered unannounced. Appalled by Don’s living conditions and by Jill scampering about in underwear, Florence caustically berates her son and rudely questions Jill about her background, insinuating that she is an unsuitable companion. When Florence then refuses to continue supporting Don financially and starts packing up his belongings to return home, Don announces that he will make his money from songwriting, lunges for the bag fruitlessly and then gropes his way out the door, humiliated. Inviting Jill to lunch, Florence suggests that Jill’s inability to sustain a relationship will only hurt Don and reminds her that she only knows Don in his own environment, not in unfamiliar ones, in which he becomes panicked. When Florence demands that she leave her son, Jill retorts that although she might not be the right woman for Don, Florence dwells only on the negative, hurting Don’s self-confidence. Late that night, as she waits with Don for Jill to return for their scheduled dinner, Florence, moved by Jill’s candor, asks Don if as a mother she has given him confidence. Hearing traces of his earlier conversation with Jill, Don accuses Florence of secretly speaking with Jill to scare her off. Jill finally arrives hours late with Ralph and announces that she is moving in with Ralph. After explaining that she received a small role in the play as a nude heroin addict, Don questions why she must be nude, carefully suggesting that she is being manipulated. Ralph quickly intercedes, explaining that the avant-garde theater piece will be misunderstood by “giddy little matrons in Hillsboro,” unaware that Florence is from the wealthy enclave. Unruffled, Florence retorts that she has little interest in his work. Jill further shames Don by asking him to feel Ralph’s face to see how handsome he is. After the couple leaves, a crushed Don begs his mother to take him home with her, but Florence reminds him that girls walk out on sighted men as well. She then explains the reason behind creating “Donnie Dark.” When, as a boy, Don became afraid of swimming, Florence created a story in which “Donnie” overcame his fear of water, and after Don returned to the water as a consequence of the story, Florence continued writing to help him overcome other obstacles. She admits that she finds it difficult to accept not being needed anymore, but finally leaves after a warm embrace with her son. Moments later, Jill rushes in with her suitcases to say goodbye. She confesses that, despite sex with Ralph being merely like Labor Day, life with Ralph requires less commitment and she is afraid of hurting Don. Don frankly states that he would rather be blind than as emotionally crippled, causing Jill to rush out. While Don listens to “Butterflies Are Free” and breaks down crying in disappointment and rage, Jill returns. She jokingly explains that she has had shadow vision and stopped cold in front of an obstacle hindering her: Ralph. They laugh and embrace with the promise of a loving and committed relationship.