In 1955, set against the picturesque backdrop of the English countryside, impoverished widower William Smith lives with his young son, Danny, in an old vardo positioned behind their small garage and filling station. The local affluent entrepreneur, Victor Hazell, who has monopolized the surrounding land, presses William to sell his land, but he stands his ground and refuses to yield.
In retaliation, Hazell deploys a series of inspectors to trouble William, accusing him of selling substandard gasoline. When this strategy backfires, Hazell resorts to insinuating to local Child Welfare agents that William is an unfit father and that his home is inappropriate for Danny. However, after observing the tidy condition of their vardo and witnessing Danny skillfully repairing their dilapidated car, the agents decide against a full investigation. One sympathetic agent even advises William to “hang in” to his piece of land.
As the school term progresses, Danny discovers a troubling secret about his kind-hearted headmaster, Mr. Snoddy, when he unwittingly delivers a car repair bill that reveals Snoddy's penchant for gin. Their innocent agreement to keep this secret results in Danny being late for class. There he faces the wrath of the stern new teacher, Captain Lancaster, who punishes him with a warning. On another occasion, for helping a rabbit escape a trap, Danny's lateness earns him an outrageous punishment of 1,000 lines.
Meanwhile, one night, William sneaks out of the vardo to engage in some light-hearted poaching of Hazell's pheasants, an echo of his past with his late father during the Great Depression. Worried for his father's safety, Danny waits up until William returns and hears about the adventure. William reassures Danny he can join in on these escapades, provided he's informed beforehand.
However, when William fails to return one late night, Danny awakens and takes the initiative to search for him in their repaired old Austin 7. Evading pursuing officers who realize he’s too young to drive, Danny manages to find refuge in the dense woods of Hazell’s estate. There, he overhears two gamekeepers discussing a poacher caught in an illegal pit trap and hurriedly makes his way to find William, who has unfortunately injured his ankle in the trap. Together, they return home, where they receive care from Doc Spencer.
As tensions rise, Captain Lancaster mistakenly assumes Danny is cheating during a test, leading to a severe punishment. Fortunately, Mr. Snoddy intervenes, threatening Lancaster with repercussions—corporal punishment is not acceptable in their school. Later, upon learning of Hazell’s extravagant pheasant shoot to impress local nobility, the Smiths hatch a plan to outsmart him by poaching the pheasants beforehand, thereby causing public embarrassment.
Danny devises a clever strategy using sedatives prescribed to William and they work late to prepare the bait. The next day, though Danny falls asleep in class due to exhaustion, he escapes Lancaster's follow-up punishment. In a comical series of events, Lancaster finds himself in a humiliating position, leading him to resign from the school.
On the eve of the pheasant shoot, William and Danny successfully drug and capture a multitude of pheasants, concealing them in the garage. The following morning, Hazell is met with utter astonishment when his guests find no quarry to shoot except for a lone sparrow. Inquisitive, Hazell dispatches his gamekeepers to hunt for the missing birds only to find themselves entertained by the chaos that unfolds as the drugged birds begin to fly around.
As tension mounts, with Hazell demanding William's arrest, the local police, led by Sergeant Enoch Samways, remind him of the legalities regarding game ownership. It comes to light that William's heroic stand in refusing to sell his land has inadvertently safeguarded the village from Hazell's nefarious plans to demolish it for a lucrative development. In a gesture of mercy and triumph, Danny releases the captured birds, leading to a joyous celebration among the villagers while a outraged Hazell drives away, thoroughly humiliated.
