But not long after the attack had begun the plan started to go awry. Canadian units lost their way in the dark. The haze of dust and smoke manufactured by the bombing and hundreds of vehicles made it almost impossible for the troops to get their bearings. Many casualties resulted, but most of the Canadians reached their objectives villages in which their comrades had previously fallen, as well as the infamous Verrières Ridge by the middle of the day. They then repulsed the inevitable German counterattacks.

The operation reaped some initial rewards, but the prolonged confusion on the congested and murky battlefield, combined with obstinate enemy resistance, soon robbed it of momentum. In his plan, Simonds expected air support would break the logjam. Unfortunately, American Flying Fortresses accidentally dropped some of their bombs on Canadian and Polish troops, killing or wounding 300 of them.

To prevent the attack from petering out completely, Simonds ordered infantry from The Algonquin Regiment, piggybacked on tanks of The British Columbia Regiment, to occupy the high ground near Quesnay Wood that rose above the main road from Caen to Falaise. Once again, however, the units got lost trying to advance in the black of night and on August 9 stumbled into the midst of the depleted but relentless 12th SS. Cut off in an open field with nowhere to hide and no chance to dig in, the Canadians fought gallantly but were systematically demolished. Over the course of the day, they lost 240 men killed, wounded, or captured, and 47 tanks.

On August 10, The Queen's Own Rifles and The North Shore Regiment attempted to clear the enemy from Quesnay Wood. On one side of the woods, the Hitler Youth waited until the last minute and then attacked the Queen's Own. On the other side, the North Shores suffered equally. The Canadians had not flinched but altogether they sustained 165 casualties including 44 killed. Simonds' attack had stalled.

In the interim, the doomed German offensive against the American front had failed miserably and, Hitler's orders notwithstanding, enemy forces had instinctively begun to flee eastward. Their pocket was gradually contracting, and unremitting Allied air attacks made life for the Germans caught inside this "Cauldron" unbearable. But every day that the inferno's exit point at Falaise remained open allowed more of them to escape. It was imperative that the Canadians take the town.

Simonds therefore launched his second major attack, Operation "Tractable". This time the plan called for a daylight assault under a smokescreen with two armoured groups in the lead, accompanied by infantry in their Kangaroos. Considerable air and artillery support were to assist them. Speed and secrecy were of the essence.

Bad luck again dogged the Canadians. Just as the attack got underway on August 14, Allied aircraft once again mistakenly bombed Canadian and Polish soldiers causing almost 400 casualties. As the armoured phalanx zoomed ahead, struggling to maintain direction through yet another dense shroud of smoke and dirt, German guns pelted its tightly packed columns. Almost oblivious to the mayhem around them, the Canadian tanks lumbered onward until they reached the Laison River. The armour became mired on the banks and bed of the stream, but in a gritty display of initiative and improvisation the Canadians forded the river.

For once, enemy resistance melted before them. These surrendering German soldiers had only recently arrived from Norway to be tossed pell-mell into battle. The next day, however, suicidal remnants of the 12th SS reminded the Canadians that the battle in Normandy was not yet won. "All ranks of [The Canadian Scottish Regiment] now stepped into a molten fire bath of battle", the unit's war diary observed. "Few prisoners were taken; the enemy preferred to die rather than give in." The Canadian Scottish suffered its worst losses since D-Day.

Meanwhile, the Americans reached the prearranged boundary line between their army and the Canadians'. There they halted so as not to collide with their ally. That still left a 30-kilometre gap between the two of them, and now the Canadians had to plug it to complete the encirclement of the substantial German units inside the shrinking Falaise pocket. As had been so often the case in the preceding two months, the Canadians were at the centre of events at a pivotal moment. Every second counted now that Hitler had grudgingly given permission for his weakened and weary troops to try to squeeze through the gap to safety. The Canadians were as determined to block their way as the Germans were to keep it open. The climax to a bloody campaign ensued.

On August 16, the 2nd Canadian Infantry Division set out to take Falaise. The following day, its ruins finally fell. Meanwhile, the 4th Canadian and the 1st Polish Armoured Divisions hurried to block the German line of retreat just east of the town. As American and Free French forces sped from the south toward Chambois, the 4th Canadian Armoured occupied Trun from the north on August 18. While the division prepared a line of defence along the Falaise Trun Chambois highway to bar the Germans from breaking out of the pocket, most of the 1st Polish Armoured took up position further east to head off the imminent enemy attempt to break in and extricate their comrades. The rest of it drove on to Chambois and there joined forces with American troops on August 19.

The Falaise Gap was closed at last, but a few small and dispersed openings remained to be plugged by the Canadians and Poles. And for that task they were on their own, trying to fend off two converging enemy forces bent on their destruction. The bulk of the 1st Polish Armoured Division to the east of the Canadian line occupied a wooded hill which its General named "Maczuga", or "mace". It was here that the Poles intended to force the Nazis into submission. But there would be a battle of epic proportions. Throughout August 20, German units able to slip past the Canadians, together with SS troops on the other side of the gap, stormed the Polish position ceaselessly. Surrounded, and running low on food, fuel, and ammunition, the Poles held fast until relieved the next day by The Canadian Grenadier Guards. In all, they lost 2,300 men. But in a stunning display of valour, the unwavering Polish soldiers had sealed the fate of the German forces in Normandy.

By then, the Canadians to the west had ended the enemy hopes of retreat. Exceptional heroism and sacrifice had been in abundance here as well. On August 18, armoured cars of The South Alberta Regiment and infantry from The Argyll and Sutherland Highlanders of Canada left Trun for the village of St. Lambert Sur Dives, just north of Chambois. Through it ran the last road out of the pocket.

Over the next two days, outnumbered and isolated Canadians waged war against a desperate enemy. It was David Currie, the thirty-two year old commander of the South Alberta Regiment, who made the difference. With all his officers either killed or wounded, Currie popped up all along the Canadian line, shouting encouragement to his thinning ranks and directing the fire of his few remaining guns. He even single-handedly knocked out one of the giant German Tiger tanks. "We knew at one stage that it was going to be a fight to the finish", one of Currie's men later recalled, "but he was so cool about it, it was impossible for us to get excited."

When it was all over, Currie and his tiny band of soldiers had destroyed seven enemy tanks, 12 of the fearsome 88's, 40 vehicles, and had killed, wounded, or captured almost 2,000 Germans. For his "courage and complete disregard for personal safety ...his conspicuous bravery and extreme devotion to duty", Major David Currie was awarded the Victoria Cross, the highest military decoration in the British Commonwealth.