The film opens with two men running across a beach at dawn, it also appears that their hands are tied behind their backs. After several shots of a helicopter frantically searching the landscape, it becomes apparent that the two men are escapees of some kind. It is later revealed that their names are MacConnachie and Ansell. The two continue running across barren land, trying to escape the sight of the helicopter. MacConnachie continuously berates Ansell as they run, showing that he is the leader, more or less.
The duo eventually get away from the helicopter and find a goat herder. MacConnachie sneaks up and kills him hoping to find any useful supplies, but does not find anything. The action, however, greatly upsets Ansell. They continue on through harsh terrain, sometimes being found by the helicopter, but they manage to escape again.
One night, they come across a small town. They sneak through, and get into a house, where the only inhabitant is a lonely widow sitting in a chair next to the bed of her presumably deceased husband. She doesn't seem to notice they are there, but she does however seem to be guarding a basket of bread. The two ignore her and loot the house, finding many supplies and even a rifle. While Ansell prepares to leave, MacConnachie takes a piece of bread from the woman's basket, causing her to drop out of her trance and scream, causing them to flee as the townspeople are alarmed. At the town limits, Ansell tells MacConnachie that he wants to continue travelling with him, which is against MacConnachie's idea of splitting up. He eventually consents and the two continue on.
They come across the helicopter again in the mountains. They come up with a plan for Ansell to distract the helicopter while MacConnachie shoots its gas tank in order to destroy it. Ansell goes to distract it, but instead of shooting the gas tank, he shoots the observer who was in the helicopter's passenger seat. Ansells protests, but MacConnachie tells him that he did it to show power over the helicopter and to not injure Ansell in a possible explosion. They also find a sub machine gun with the observer's dead body.
After being pursued by ground troops through a field, they then come across a military compound where the helicopter goes to refuel. They try to sneak through, but are caught, and are forced to fight and escape, in the process shooting up the parked helicopter. They continue travelling across a mountain range afterwards where the ice is melting.
Eventually, they arrive at a snow peaked mountain, which seems to be what they were searching for the entire trip. At the top there is a military post, presumably at the border, and several soldiers who come out to greet them. Ansell is overjoyed and runs out to them, though MacConnachie hears a kind of noise from behind him, which is the helicopter. Before joining Ansell, he decides to stage a last stand battle between himself and the helicopter. Despite shooting it many times, the helicopter fires at MacConnachie, killing him. Ansell feels remorse, but eventually returns with the soldiers to the compound.Robert Shaw - MacConnachie
Malcolm McDowell - Ansell
Henry Woolf - Helicopter pilot
Christopher Malcolm - Helicopter observer
Andy Bradford - Soldier (credited as Andrew Bradford)
Warwick Sims - Soldier
Roger Lloyd-Pack - Soldier
Robert East - Soldier
Tariq Yunus - Soldier
Pamela Brown - Widow
The production took four months to film, between June and October 1969. It was shot in Sierra Nevada, Granada, Andalucia, Spain. During pre-production, many of the film's crew were replaced, such as Peter Medak as director and Peter O'Toole as star. At the time of filming, Robert Shaw was a quite well known star, whereas Malcolm McDowell was still relatively unknown, being that it was made in the period after If.... but before A Clockwork Orange.
The film was quite revolutionary with its use of mystery to the audience; the characters, background, and location all go unknown throughout the entire film. The only information on the characters is revealed through dialogue. Whereas the book reveals the characters to be soldiers, this never comes up in the film. The film also makes much use of long takes, mainly in the shots which take place in the helicopter, the long takes signify the helicopter's long search.