Unable to find the old man outside of the church, Antonio begins to lose all hope of finding his bicycle. Bruno pointedly asks his father, “Why’d you let him [the old man] go for his lunch?” and Antonio slaps him out of frustration. Bruno runs off crying, immensely hurt by Antonio’s actions. While standing behind a tree, Bruno asks his father why he hit him, to which Antonio replies, “You asked for it.” Bruno says he’s going to tell Maria what Antonio did to him. Refusing to demonstrate any empathy, Antonio ignores Bruno’s pain, asking his son to wait for him by the bridge while Antonio continues his search for the old man.
When looking for the man along the lake, Antonio suddenly hears different voices crying, “Help! A boy’s drowning!” Antonio, having lost track of his son’s whereabouts, begins to fear Bruno is the drowning boy. He exclaims Bruno’s name and begins to anxiously run toward the group of crying people to find out if his son is in danger. While approaching the group, Antonio runs under a tunnel, an image which reminds us of his initial quest to find his bike earlier in the film.
A group of young boys and a fisherman retrieve and save the drowning boy, who is revealed to be someone other than Bruno, much to Antonio’s relief. Bruno sits at the top of the stairs, and Antonio—now remembering his love for his son—runs toward him. Antonio offers pizza for lunch to a still noticeably upset Bruno in an attempt to cheer him up. Antonio understands that taking his son out to a fancy restaurant will put a strain on his wallet, but he decides to neglect all of his predicaments, stating, “Why kill myself worrying when I’ll end up just as dead anyway?”
Antonio and Bruno arrive at a trattoria, a formal restaurant complete with a live orchestra and bourgeois, well-dressed customers. While Antonio and Bruno both realize that they don’t belong at such an upscale restaurant, Antonio urges Bruno to sit down, exclaiming, “Let’s forget everything and get drunk!” The waiter approaches the duo, and Antonio orders 2 mozzarella cheese sandwich and a bottle of wine. Bruno notices a snotty, wealthier child in the restaurant, who eats a large plate of pasta and periodically glares at Bruno and Antonio. In spite of the boy's condescending gaze, Bruno shows excitement for the meal.
Antonio compels his son to drink wine, and they both laugh at the thought of Maria seeing their impulsive behavior. Unable to figure out how to use utensils, Bruno eats the mozzarella cheese sandwich with his hands. After noticing Bruno's anxious glances at the other boy and his wealthy family, Antonio states, “To eat like them, you’d have to earn a million lira a month.” This comment worries Bruno, who stops eating his sandwich. His father too becomes engulfed with self-doubt and remorse, having Bruno calculate his decent salary if Antonio had been able to proceed with his job. Realizing the bike’s significance in ensuring his family’s well-being, Antonio and Bruno leave the trattoria and continue their quest to find the bicycle.
Desperate, Antonio and Bruno visit the seer from the film’s opening scenes. Antonio previously ridiculed Maria for believing in the seer’s abilities, but he now views the “holy one” as the last resort for providing proper insight and guidance into the location of his bike. The seer’s bedroom is full of people seeking her services. The "holy one" tells one young man that the woman he loves doesn’t love him back. She then brutally tells the man, “My dear boy, you’re very ugly. Very ugly. There are so many other women. Sow your seeds in a different field.” Dissatisfied and baffled, the man meekly pays the seer and leaves.
Bruno then rushes to the seat where the man was sitting and says, “Daddy, come on! There’s room now!” to Antonio. Despite other customers' insistence that Antonio and Bruno can’t skip the line—especially when people have been waiting for hours—Antonio cuts anyway. He tells the seer about his stolen bicycle, who rebuffs his predicament and bluntly states, “Either you find it right away or you never well...I don’t know what else to tell you. Go now, and try to understand.” Antonio offers the seer the last of his money and exits the seer’s apartment with Bruno.
Part 4 of Bicycle Thieves somewhat departs from the plot-driven odyssey to find Antonio’s bicycle; it instead zooms in on his delicate, deeply-affecting relationship with Bruno. For most of the film, Bruno is characterized as a small adult. His poverty-stricken family lives in dire conditions, which prevent him from living a typical, carefree childhood and thereby propel him to become rational and self-sufficient. Ironically, at the beginning of the film, he is the only employed member of his family, working at a gas station to support Antonio, Maria, and his infant sibling. Humbly forced at work at a young age, Bruno is the antithesis of the snotty, bourgeois child in the trattoria, and his first appearance immediately establishes him as a responsible, concerned adult. He cleans Antonio’s bike and is familiar with all its specific features and taunts his father's passiveness for not confronting the pawn shop employee about the new tiny dent in the frame. Before leaving for work, Bruno closes a window so his infant sibling will stay warm and not catch a cold. At the plaza, he is sensible enough to ignore the squirrely-looking pedophile, who offers to buy him a new shiny bicycle bell. Bruno seems to be capable of taking care himself, with his characterization highlighting a responsibility and concern that equals his adult counterparts.
However, Antonio doesn’t treat his son like an equal; he barely pays any attention to him at all throughout the film. Bruno, while admiring his father, is in the unfortunate position of witnessing Antonio indulge in some of his most severe shortcomings, namely his carelessness. So obsessed with his own self-pity and distraught by his stolen bicycle, Antonio constantly outpaces Bruno while roaming around labyrinthine Rome. He does not notice when Bruno falls to the ground in the rain; he does not notice when the pedophile badgers an unsupervised Bruno; and he does not notice when (later in the film) two cars nearly run over Bruno. Alas, Antonio treats his son just like his bicycle—inattentively. By failing to pay proper attention to Bruno, Antonio’s actions even suggest that he places more value and concern toward his missing bike than his own kind, loyal, and independent son. When Antonio projects his frustration onto Bruno and slaps him, we see the truly guileless and childlike dimensions of Bruno’s personality unfold. He moves away from Antonio crying, latches onto a tree out of simultaneous defiance and fear, and tells Antonio he will tell Maria on him. This is no longer the self-sufficient, employed, and paternal small adult; this is a child tearfully reacting to the dehumanization and abuse inflicted by his biggest role model, his father.
Likewise, the slapping of Bruno also cements a turning point for Antonio’s character. While we identify with Antonio’s struggles, we cannot condone his mistreatment of Bruno, which reveals Antonio to be a seriously flawed, albeit human, protagonist. At this point, through his demonstrated short temper and neglect of Bruno, he no longer upholds the high moral standards exhibited in the beginning of the film. Instead, his self-pity renders him oblivious to the suffering around him, particularly the most important person in his life: Bruno.
This section of the film suggests that the fate that befell Antonio’s bike could befall Bruno, too, due to Antonio’s negligence. Antonio is finally shocked into parental concern when he realizes he does not know Bruno’s whereabouts and hears that a boy is drowning in the nearby river. When Antonio races to the commotion to see if Bruno is indeed the drowning boy, he runs under a vast tunnel. The imagery of the tunnel evokes the scene where Antonio’s bike is stolen in Part 1, wherein Antonio latches onto a car to chase the thief underneath a tunnel. Thankfully, the results of Antonio’s panicked search for his son do not match those of the doomed and unsuccessful pursuit of his bicycle, with Antonio breathing a sigh of relief upon seeing Bruno sitting at the top of the immense stairs. The low camera placement and wide-angle lens makes Bruno appear precious and fragile, symbolizing Antonio’s newfound remembrance of his love for his son. However, despite the scene’s cathartic and reassured ending, De Sica nonetheless reminds us that Bruno was not the boy in danger, but he easily could have been. Antonio’s carelessness previously resulted in the disappearance of a valuable possession—his bicycle—but its persistence could lend itself to much a more dire and devastating outcome—the death of his son.
Notably, Part 4 also entails structural repetition. We see this in the aforementioned imagery when Antonio runs under the tunnel, but the repetition explicitly surfaces when Antonio visits the “holy one.” His decision to receive advice from the seer reflects the ill-fated linear progression of Antonio’s odyssey, as well his increasing despair and evolution in character. In Part 1, Antonio, who feels prideful after reclaiming his bicycle, cynically dismisses the seer as rubbish and ridicules Maria for feeling obligated to pay her. However, the trials and tribulations of Antonio’s hopeless quest to find his bicycle leaves him utterly desperate, with no other choice but to rely on the services of the “holy one.” When he and Bruno visit the apartment of "the holy one," they encounter many other people waiting to receive her foresight, displaying a faith in spirituality when other institutions (employment services, the police, the government) have failed to offer security and hope. The seer’s advice to Antonio, however, is simple and insubstantial. The “wisdom” she provides shares stark similarities to what Antonio hears from Baiocco, who tells him that he will either find the bike immediately or never. Unmoved by this advice, Antonio and Bruno leave the apartment dissatisfied, illustrating that neither pragmatic functionaries and spiritual services are able to help them. This leaves Antonio and Bruno more helpless and alienated than ever, which hints at the film’s equally downbeat, sorrowful finale.