In 1961 New Castle, Kempton Bunton, a 60-year-old taxi driver with a penchant for challenging societal norms, finds himself embroiled in an extraordinary heist. The government acquires Francisco Goya's painting of the Duke of Wellington for £140,000, intending to exhibit it publicly. Kempton, disgruntled by what he perceives as government waste and their neglect of issues like free television licenses for seniors, formulates a bold plan to liberate the painting from its prestigious home at the National Gallery. His intentions are more altruistic than self-serving; he believes the theft will spur public debate and lead to greater societal changes, aligning with his long-standing activism against financial injustices.

As Kempton attempts to navigate the ensuing moral and legal dilemmas, he must keep his family in the dark, particularly his devoted wife, Dorothy. However, Kempton's lack of criminal experience and penchant for accidental trouble complicate his grand scheme. Tensions rise as the police investigation intensifies, garnering public fascination and pressuring Kempton to maintain his secrecy and ultimately decide what kind of legacy he wishes to leave. The painting becomes a symbol of resistance, placing Kempton at a crossroads between personal conviction and familial duty. As events unfold, the audience is led through a heartening journey exploring themes of justice, identity, and sacrifice while highlighting one man's quest for recognition and purpose.