In this short story, a father and his six year old daughter are eating peaches together when "two feelers" appear from the cavity of the peach seed. The feelers soon emerge, followed by the body of a brown bug, which fascinates the little girl. It isn't clear what type of bug this is, as the narrative is largely from the limited perspective of a child, but the bug is brown, has "a knob head, feelers, and a great many legs."

When the bug has climbed down the side of the peach and onto the plate, the little girl asks, "Who is it?" to which her father replies, "Gaston." In response to his daughter's suggestion that they should squash him, because that is what is generally done with bugs, the father argues that this is "Gaston the great boulevardier" and that they should take pity on him, as he is now homeless. He explains to his daughter that Gaston has previously been very well set up in his house in the peach seed, whereas now he is "out in the world and out on his own."

The little girl is so captivated by her father's flights of imaginative fancy about Gaston that she demands another "peach with people," causing her father to leave the house in search of a flawed peach. While he is away, the little girl's mother calls her, and her disapproval of the father's behavior punctures the little girl's enthusiasm for peach-bugs and specifically Gaston, who "was all ugh, as he had been in the first place." By the time her father returns, she has squashed Gaston, disillusioned by her mother's words, and announces that a car will soon arrive to take her to "a birthday party," and then back to New York. She is no longer interested in the peaches he has found, and the father is left deflated, feeling "a little, he thought, like Gaston on the white plate"—that is, "confused," "entirely alone," and unsure what to do with himself.