In late August, Wolfe and his brigadiers agreed to cross the St. Lawrence River west of the city. Numerous soldiers had already boarded the ships and drifted up and down the river for several days when Wolfe made the final decision on September 12 and his choice of landing site was Anse au Foulon. This small cove is located southwest of town at Sillery, about three kilometers from Cap Diamant. It is located at the foot of a 53-meter-high cliff that merges into the plateau above; it was protected at the time by a battery of cannons. It is not known why Wolfe chose this site, as the landing was originally planned further upstream. There the British could have set up a beachhead and moved against Louis Antoine de Bougainville's troops encamped farther west, thereby luring Louis-Joseph de Montcalm out of the city and onto the high plateau. According to Brigadier George Townshend, the general had changed his mind based on scouting reports. In his last letter, dated September 12 at 8:30 p.m. on HMS Sutherland, Wolfe wrote:
"I had the honor to inform you today that it is my duty to attack the French army. To the best of my knowledge and ability, I have fixed upon that spot where we can act with most force and are most likely to succeed. If I am mistaken I am sorry for it and must be answerable to His Majesty and the public for the consequences."
"I had the honor to inform you today that it is my duty to attack the French army. To the best of my knowledge and belief, I have chosen that place where we can act with the greatest strength and are most likely to succeed. If I am wrong, I am sorry and will have to answer to His Majesty and the public for the consequences."
Wolfe's plan of attack depended on secrecy and surprise. A small group was to go ashore at night on the north shore, climb the steep slope, occupy a small road and overwhelm the garrison standing guard there. The bulk of the army (5000 men) was to climb the slope via the small road and then form up on the high plateau. Even if the first group succeeded and the army managed to follow it, his troops would be placed inside the French defensive line - with the river as the only means of retreat. It is possible that Wolfe's decision to change the landing site had less to do with a desire for secrecy than with his general disdain for his brigadiers (a feeling that was mutual). He may also still have been suffering from the effects of his illness in the second half of August and the opiates he took as painkillers. Historian Fred Anderson believes Wolfe ordered the attack in the belief that the advance guard would be repulsed and that he expected to die chivalrously with his men rather than return home in disgrace.
Bougainville, charged with defending the extensive plateau, was with his troops farther upriver at Cap Rouge on the evening of September 12 and did not notice the numerous British ships drifting downriver. A group of 100 militiamen under the command of Captain Louis Du Pont Duchambon de Vergor had been ordered to patrol the narrow road at Anse au Foulon, which followed the bank of the Saint-Denis creek. On the night of September 13, there were probably just 40 men at their post, as the others were busy bringing in the harvest. Vaudreuil and others had expressed concern about the possible weak point at Anse au Foulon, but Montcalm dismissed them, saying 100 men were enough to hold off an army until sunrise. He commented, "The enemy cannot be expected to possess wings, so that in the same night he would cross the river, disembark, climb the obstacle-strewn slope, and scale the walls, carrying ladders for the latter."
Guards actually spotted boats on the river, but they were expecting a French supply convoy - a plan that had been cancelled without Vergor being informed. When the first boats landed, the crew was asked to identify themselves. To this, an excellent French-speaking officer of the 78th Fraser Highlanders responded and allayed suspicion. The boats had gone a little off course. Instead of landing at the end of the road, numerous soldiers found themselves at the bottom of a slope. A group of 24 volunteers led by William Howe was sent out to clear the fence along the road and climb the slope. This allowed them to emerge behind Vergor's camp and quickly capture it. Wolfe followed an hour later when he was able to use a convenient access road to get to the plateau. By the time the sun rose over the Abraham Plateau, Wolfe's army had a solid base above the slope.