I once saw a homeless man take a shit outside Kings Cross railway station, and swear I was the only person who witnessed what was happening. There are bigger and badder examples of social invisibility. Every now and then — it happens often enough to remind you that it’s a depressing feature of human experience — there’s a news story about how people ignore a crime that’s committed in front of them they could have stopped, or leave an injured person to suffer while getting on with their own priorities.

High Plains Drifter is about the hell visited on Lago, a nowhere town whose marshal is killed by a trio of whip-wielding badasses, when they turn to Clint Eastwood for help. There’s an echo here of the Kurosawa samurai films that Leone’s westerns were in part based on, here tangled with a morbid religiosity as befits a nation initially colonised by godbotherers seeking a new home.

It’s a wonderful example of how to bring a sense of the fantastic into a film that begins in a heightened but essentially naturalistic mode. One of the problems with cameras is that what you put in front of them seems real. The flights of fancy possible on a theatre stage, where the audience is willing to suspend their disbelief, are less often dabbled with in cinema, which is a pity. High Plains Drifter, directed by Eastwood in 1973, shows how a story can gradually assume mythic proportions in a way that an audience can relate to.

Eastwood plays the drifter, who is all set to move on through Lago when he’s first offered the chance to take care of the bad guys. He changes his mind when he realises that they’re the same bastards that nearly killed him a while ago, and this will be a chance for payback. At which point, things get interesting…

The drifter takes over Lago, quickly establishing his authority over sheriff and mayor and appointing an overlooked dwarf to those roles in their place. It’s a fascinating insight into what happens when one man really does live according to his will — there’s no prevarication about the drifter, who when he sets about the task he’s been hired to do is single minded in achieving his objective. The reaction of Lago’s citizens is interesting: as Eastwood struts and demands what he’s been told is his due, the locals inhabit his aura, impressed but unable to duplicate his machismo for fear of reprisal.

At one level you could easily say this is a story about an alpha male let loose in a rural community which has lost its figurehead. But there’s much more going on than that: in preparing Lago to take on the villains, Eastwood turns the town into hell. When the trio do turn up, Lago is all crimson and flames, presided over the drifter who picks his enemies off one at a time, disposing each of them with the whips that they’ve tormented others.

Make no mistake, Eastwood is a bastard — but the people of Lago had it coming. The drifter is an angel of vengeance sent to punish them, whether by buying rounds of drinks at the bartender’s expense, or rape — he will stop at absolutely nothing in enacting his will. It’s visceral stuff, the rape in particular a shock for modern audiences, and the whole is undeniably powerful.

The picture of hell presented here makes the western’s flexibility clear. Some writers on genre reckon that the western (along with science fiction) is a setting rather than a genre, and that makes sense in this case at least. You could tell the same story, as alluded to, in a Japanese feudal setting, or make it a contemporary tale with gangster trappings. What matters is the heart of darkness beating at the story’s centre, and the commitment of writer (Ernest Tidyman in this case: he also created Shaft in the black detective’s prose incarnation) and director to realising a vision of hell for a secular audience.