Late summer 1944. German units are routed, fleeing from the lost battles in Normandy to the borders of Germany and Holland. The Allies are now certain of victory and believe the war might be over by Christmas 1944. But in the months to come they are faced with a series of bloody surprises.

It begins in September with a daring British land campaign: tens of thousands of British and American troops land near Arnhem, Nimwegen and Eindhoven on 17 September 1944. Their targets are the strategically vital bridges over the rivers Maas, Waal and Rhine, which are important channels of communication for the Allied forces, under British Field Marshall Montgomery, as they advance into the Ruhr region.

The British believe at this point that the German forces are no longer any real military threat, consisting only of scattered, demoralised and disorganised units short of both weapons and equipment.

At first the British attack has the benefit of surprise, but then the Germans consolidate their forces to provide resistance - much to the surprise of the British, whose military intelligence department had entirely failed to notice that there was an SS tank regiment in the region. The British parachute troops hold the bridge at Arnheim against vastly superior German forces for five days. Bit by bit they are encircled, and final phase of the fighting is a bloody street battle.

In this programme former British soldiers attempting to hold the bridge tell their story.

On 26. September 1944 the Battle of Arnhem is over. While the Americans are able to form a bridgehead at Nimwegen, the British suffer a disastrous defeat. But Hitler is triumphant. Arnhem is the first German "success" in the west since the Allies landed in Normandy. His illusion that final defeat can still somehow be avoided is given new impetus.

During these weeks and months American troops also suffer a bitter setback. During autumn and winter 1944 the Hurtgen Forest on the western border of Germany becomes the final resting-place of almost 20,000 GIs and 12,000 German soldiers.

American troops had actually reached the border of the German Reich as early as 12 September 1944. The American generals are beginning to hope they could march into Berlin in a matter of weeks. Victory seems very close. But the advance is halted.

The GIs are better equipped but exhausted and victims of bad intelligence; in the forests to the south of Aachen they come across well-camouflaged bunkers, part of the "West Wall" line of defence, and for months on end the Americans suffer heavy losses without advancing. And the aim of their mission is of only minor military importance: to knock out two dams.

The kind of forest fighting that has to be waged here is completely new for the Americans. Their troops have not been trained for this and do not have the necessary equipment.

Today former GIs complain angrily about incompetent leadership on their own side. And yet, even in the Hurtgen Forest, there are moments of humanity. What happened there in November 1944 is still known as "The Hurtgen Miracle" by US veterans: trucks were driven over to enemy positions so that wounded men could be exchanged. And yet... to this very day "The Hurtgen" is an American trauma.

On the morning of 16 December 1944 the US forces were surprised by a German counter-attack, the Ardennes Offensive.

German troops are attacking, for the first time since the western Allies landed in Normandy. Hitler has ordered the last reserves of the German Army to be mobilised for this venture, calling on battle-hardened units from the Eastern Front - and this plunges the Allies into the most serious crisis they have experienced since they landed on the European mainland on D-Day.

Thousands of heavy guns mount a deadly artillery barrage. Shells shatter the Allied lines of supply and channels of communication. Chet Hansen describes the utter amazement of the Allied military commanders when they realise how powerful the German offensive is.

Several German units advance recklessly to the west - including one SS unit known as the Peiper Brigade, who use stimulants like the drug pervitin. Whenever Peiper's men appear, a bloodbath is the result. Like the massacre of US prisoners at Malmedy. One of the victims who survived, a GI called Albert Valenzi, has always remained silent on the subject of that terrible day - but in this film he explains that he only survived because the dead bodies of his fallen comrades stopped the machine-gun bullets meant for him.

SS soldiers also commit atrocities involving civilians, as recounted by Arlette Mignon, survivor of a massacre of Belgians Stavelot when almost 100 civilians were murdered in cold blood.

But even outrages like these cannot prevent the ultimate failure of the offensive. After just a week the tide turns in favour of the Allies. The bad weather that has lasted for several days finally clears up, so American planes can mount attacks once again.

The city of Bastogne, besieged by the Germans, is relieved. The city had been defended with astonishing obstinacy by parachute forces of the 101 US Air-Land Division. The German ultimatum calling for capitulation was met with a response by US General McAuliffe that has become legendary: "Nuts".