The central twist of High and Low occurs early: the kidnapper has mistakenly taken Shinichi, the son of Gondo's chauffeur, Aoki, instead of Gondo's own son, Jun. This transforms the narrative from a standard kidnapping plot into a profound moral quandary. Gondo's decision to pay the ¥30 million ransom, an amount he has mortgaged his entire life to raise for a corporate takeover, leads to his complete financial and professional ruin.
The second half of the film is a meticulous police procedural. The police recover the child after a tense ransom drop from a moving bullet train, a sequence filmed with incredible precision. The kidnapper is identified as Ginjirō Takeuchi, a medical intern from the slums. The police discover he had two accomplices, both heroin addicts, whom he murdered by giving them an overdose of pure heroin. To trap Takeuchi, the police plant a fake news story suggesting his accomplices are still alive and then forge a note from them demanding more drugs. The trap works, and Takeuchi is arrested after trying to dispose of another addict with a lethal dose.
The film concludes with a final, searing confrontation in prison. Gondo, now working for a rival shoe company, meets Takeuchi, who is on death row. Takeuchi confesses his crime was born of envy from seeing Gondo's house, a 'heaven' that made his own squalid life feel like 'hell.' He tries to maintain a detached superiority but finally breaks down into hysterics, a screaming, tormented figure, as a metal grate slams down, separating the two men and sealing Takeuchi's fate. This ending reveals the crime was never about the money; it was an act of desperate, nihilistic class warfare. Gondo may have lost his wealth, but he has been morally redeemed, while Takeuchi, the man from the 'low', is consumed by the hell of his own making.