The long-distance phone lines at the hotel are busy, so Muriel Glass has to wait two and a half hours for her call to go through—time that she spends reading a magazine article about sex; grooming herself; cleaning her clothes; and painting her nails. When the operator finally rings her room, Muriel is unhurried in getting to the phone and leisurely puts the finishing touches on her manicure. Careful to keep her freshly painted nails away from the fabric of her silk dressing goal, Muriel picks up the receiver, and the operator connects Muriel’s call to New York.
On the other line is Muriel’s mother, who is beside herself with worry and berates Muriel for not calling sooner. Muriel begins to explain that she’s called a few times, but her mother cuts her off, frantically asking Muriel if she’s alright. She demands to know who drove; Muriel admits that her husband, Seymour, did—but she assures her mother that he drove appropriately and didn’t run into any trees. After alluding to an incident in which Seymour crashed Muriel’s father’s car, Muriel asks her mother if she’s seen a book of German poems that Seymour sent her while he was away at war. Muriel and her mother laugh about how Seymour expected Muriel to read poems in a different language.
Muriel’s mother gravely explains that Muriel’s father consulted Dr. Sivetski about Seymour’s recent behavior—like when he brazenly asked Muriel’s grandmother about her plans for dying. According to Dr. Sivetski, the army made a big mistake in releasing Seymour from the hospital, and Seymour is bound to lose control of himself soon. Muriel’s mother again frets about Muriel’s well-being and begs her to come home. Muriel balks; she hasn’t had a vacation in years, so she’s not going to leave now.
Muriel shares that she met a psychiatrist at the hotel while Seymour was off playing piano elsewhere; the psychiatrist had asked if Seymour was sick, and Muriel assumed he was referring to Seymour’s pale complexion. Muriel begins talking about the man’s horrible, unfashionable wife, but her mother wants to know more about what the psychiatrist said about Seymour. Muriel doesn’t remember much of what the psychiatrist said and explains that it was so noisy in the bar they were in, she couldn’t really hear him well to begin with. Muriel’s mother again implores Muriel to spend some time away from Seymour, perhaps on a cruise. Exasperated, Muriel says that Seymour has been behaving himself—though he refuses to take his bathrobe off because he doesn’t want people looking at his tattoo, even though he doesn’t actually have one.
Meanwhile, Mrs. Carpenter is slathering her young daughter, Sybil, in sun-tan oil. Sybil keeps repeating the phrase “See more glass,” while Mrs. Carpenter’s friend chatters on about a silk scarf. Annoyed with her daughter, Mrs. Carpenter tells Sybil to run off and play, so Sybil bounds down the beach until she reaches a young man lying in the sand in a bathrobe. The man is startled but, realizing that his unexpected visitor is just Sybil, he quickly relaxes. The pair fall into an easy conversation about Seymour’s wife and Sybil’s bathing suit (which is yellow, but which Seymour mistakes for blue). As they talk, Seymour frequently touches Sybil’s feet and ankles.
Sybil accuses Seymour of letting Sharon Lipschutz, a different young girl visiting the resort, sit on the piano bench with him—Seymour admits that this happened but that he felt like he couldn’t just push Sharon off, so he pretended she was Sybil. Sybil demands that they get in the water. Shedding his robe, Seymour agrees, saying that they can catch bananafish. He asks Sybil where she lives, but when she claims to not know, he says that Sharon Lipschutz knows where she lives—and she’s only three and a half years old. Sybil answers that she lives in Whirly Wood, Connecticut but then demands to know if Seymour likes Sharon. Seymour says he does, especially because she doesn’t abuse dogs in the hotel lobby—like the one that belongs to the hotel resident from Canada. He explains that, shocking as it may sound, there are some little girls who meanly poke the dog with balloon sticks. Sybil goes quiet.
Once in the water, Seymour declares that it is a “perfect day for bananafish.” He explains that bananafish are like regular fish, but they swim into holes full of bananas. They then gorge themselves on said bananas until they’re so fat that they can’t swim back out of the holes and then they die of “banana fever.” When a wave comes, Sybil screams in delight and claims that she saw six bananafish underwater. Seymour picks up one of Sybil’s ankles and kisses the arch of her foot. Sybil yells in surprise, and Seymour says that it’s time to go back to shore, even though Sybil doesn’t want to.
After they part, Seymour dons his robe and makes his way back to the resort. In the elevator, he aggressively accuses a woman of secretly staring at his feet, and the woman nervously asks the elevator operator to let her out. When Seymour arrives to his hotel room, he’s greeted by the strong smells of his wife’s nail polish remover and calfskin luggage. He looks at Muriel sleeping on one of the beds and then digs through his own luggage, pulling out a gun, which he promptly loads. He settles himself on the twin bed next to Muriel’s, looks over at her again, and then shoots himself in the temple.