Please note: In this writeup, I discuss the entire plot of the film. If you think this will spoil the film for you, don't read on. However, I can assure you that High and Low is deeper than it's plot, and the enjoyment of the film might even be augmented by knowing what will happen in advance. But, still, you've been warned.
An arrogant and wealthy businessman, a shoe magnate, mortgages his house to buy out his business partners in order to run his factory with an Iron Hand. As he sits in his air conditioned mansion overlooking the steaming, impoverished port of Yokahama a mentally imbalanced medical student, tormented with envy, plans to kidnap and ransom his son. The plain succeeds, almost; he kidnaps the son of the businessman's Chauffer. Despite temporary relief up at the mansion, the kidnapper soon reapplies the pressure - he demands the ransom anyway, enough to ruin the businessman and ensure his poverty for life. Otherwise, the driver's son will die.
This premise, taken from an Ed Mcbain police procedural novel, becomes the beginning of one of Akira Kurosawa's most searching works of art - High and Low, also translated as Heaven and Hell The shoe magnate, played by Toshiro Mifune (the lead in almost all of Kurosawa's more well known Samurai films) at first refuses to take responsibility for the his drivers son, but as time passes, and the pressure grows, he knows that sacrificing his prosperity to save the life of his driver's child is the only possible moral solution.
If this were the end of the story, though, the movie might have been a cheap melodrama. In fact, it's expertly divided into three parts, Heaven (in which Mifune makes his agonizing moral decision) Purgatory, (in which hard working and underpaid police detectives, touched by Mifune's generosity - although one of them says, "under normal circumstances, I don't much care for the rich" - work their way through the Yokohama underclass to find the killer", and finally, Hell, in which the police track the killer down. Each of the three sections is filmed in a different style - the Heaven section with low sweeping shots and long focuses on the character's emotions; Purgatory a series of shots concentrating on the Police Procedure and finally Hell.
Hell is the masterpiece of the film, and one of the ends with one of the greatest 20 minutes of film in history. The police want the chance to put the kidnapper away for life. In order to ensure that he commits a capital crime, they deliberately allow him to murder a drug addicted prostitute while they stand by, waiting to catch him in a snare. Finally, trapped, he asks to see Mifune. Until this moment, Mifune has been set up as the superhero character common to him, a sort of Samurai in a business suit. He has sacrificed his life to fulfill his obligations, and done so without grumbling. He has acted perfectly. Now he is confronted with a twisted, envious lunatic who we, as a character, have seen only as a murderous killer. In the final ten minutes of the film, this murderer wins our pity. Mifune has been destroyed by this man, and yet he asks him, heroically, "Must we hate one another?" The kidnapper tells Mifune, as he sits behind a grate in a strait jacket, "It was so cold in the winter and hot in the summer, I couldn't sleep. I stayed alive by hating you. Hell? I'm not afraid of hell. I've lived my entire life in Hell. But send me to heaven - and then I would really be afraid." And in front of our eyes, he has a nervous breakdown. The guards come in and subdue him, and a heavy grate falls between him and Mifune, and we, the viewers, become uncomfortably aware that we have just watched a man condemned to hell. And we, as Mifune, become uncomfortably aware that whatever a man may have done, we can not lightly watch his condemnation without a shiver of guilt - a primal guilt common to all mankind - cross through our soul. In the final scene, Mifune sits stunned, looking at a big metal grate, behind which a tormented spirit mocks his heroism - while at the same time, making his heroism seem even mightier than it is.
In short, get your hands on this film, and watch it. Even if you hate foreign movies with subtitles, even if you just generally hate film. This is a must see.