In Lessing's story, the eleven-year-old Jerry braves an underwater tunnel while he and his mother are on vacation. The tunnel evolves into an enormous challenge for Jerry, as he deals with his loneliness and his attempts at separating from his mother.

Rites of Passage
Jerry's beach vacation becomes the site of an intense personal challenge. Jerry must leave his mother at the shore, the shore Jerry sees as "a place for small children, a place where his mother might lie safe in the sun." He leaves the safety of this nursery-like beach and journeys to the treacherous "wild and rocky" bay and the underwater tunnel. An eleven-year-old nearing puberty, Jerry is fatherless and approaching adulthood as the sole male of the family. Throughout the story, the interchanges between him and his mother heighten the tension of the story, but Jerry, except for the one day on the safe beach, independently controls most of the action. Like most traditional rites of passage into adulthood, Jerry must venture into the wild, braving the elements and dangers of the world by himself. When he successfully completes his swim, he returns to his mother and proudly declares that he "can stay underwater for two minutes—three minutes at least." This statement belies the danger he has faced and insures the secrecy of his personal rite.

Individualism
Jerry's ability to hold his breath may also be understood as a symbolic assertion of his independence. Jerry trains until he does not require air for minutes at a time. Breaking away from his mother allows Jerry to explore and challenge himself. He learns to swim through the dangerous tunnel by himself, without any assistance from the local boys, which establishes his independence. The young boy, who at first whines for attention later hides his bloody nose from his mother so that only he will know how dangerous his play has been. Jerry establishes his maturity through his diligence, daring, and patience and expresses it in a conventional masculine form: through physical challenge.

Alienation and Loneliness
This tension between independence and dependence parallels the stress of alienation and loneliness in the story. At first, Jerry is so desperately lonely that his desire to play with the local boys is a "craving that fill[s] his whole body." Although they beckon him closer, he is separated by language, age, and nationality. The boys eventually shun him in light of his immature antics. Jerry seems desperate for attention, yet he leaves the beach where his mother and the other tourists can be found. His loneliness is partially self-imposed. Throughout the story Jerry disdains his mother and yearns for male companionship, suggesting that he may be searching for a father figure to compensate for his deceased father's absence. Jerry fights against his loneliness, the loneliness that brings him to the tunnel, but he also embraces it by swimming to the loneliest place imaginable—the dark tunnel—by himself.