A few days passed and the month of May was ushered in. Cary Singleton was right in foretelling that stirring events were at hand. A crisis intervened in the siege of Quebec. Since the disappearance of the snow the Americans had given some symptoms of activity. There was more frequent firing upon the town, and feints were made with ladders and ropes for escalades at different points. An armed schooner, named the GaspÉ, captured during the autumn, was prepared as a fire-ship to drift down and destroy the craft that was moored in the Cul-de-Sac, at the eastern extremity of Lower Town. Other vessels destined for a similar service were also made ready. At nine o'clock on the night of the 3rd of May, the attempt was actually made. One of the fire-ships turned out from Levis, and advanced near to the Quebec shore without molestation, the garrison imagining that it was a friend. Success seemed almost within reach, when on being hailed, and not answering, guns were fired at her from the Grand Battery over the Cape. At this signal that they were discovered, the crew at once set a match to the combustible material on board, and sent the vessel drifting directly for the Cul-de-Sac. A moment more and she would have reached that coveted spot, and the shipping, with the greater part of Lower Town, would have been consumed. But the tide having ebbed about an hour, the current drove her back, notwithstanding that the north-east wind was in her favour. This failure was a terrible disappointment to the Americans. It was their last stroke against Quebec. Had the attempt succeeded, the army intended to attack the town during the confusion which the conflagration would necessarily have created, and the onslaught would have been a terrible one, because they were goaded to despair by their continuous ill-success, at the same time that they knew it was their final chance prior to the arrival of the British fleet, which was every day expected.

That fleet did not long delay its appearance. At six o'clock, on the morning of the 6th May, a frigate hove in sight turning Point Levis. The whole American army witnessed her triumphant entrance. The ramparts of the town were lined with spectators to hail the welcome sight. Drums beat to arms, the church bells clanged, and an immense shout arose that was re-echoed from the Plains of Abraham across the river to the Isle of Orleans. It was the acclamation of deliverance for the besieged, the knell of final defeat for the besiegers. The frigate was well named the Surprise, and she carried on board two companies of the 29th regiment with some marines, the whole amounting to two hundred men, who were immediately landed.

She was speedily followed by other war vessels containing more abundant reinforcements.

At noon of the same memorable day, the garrison, supported by the new arrivals, formed in different divisions, issued through the gates, and moved slowly as far as the battle field of St. Foye, where Chevalier Levis won his brilliant, but barren victory over Murray, on the 28th April, 1760. Carleton, now that he was backed by a power from the sea, shook off his inaction, and determined to deliver combat to the Continentals. But beyond a few pickets who fired as they fell back, the latter were nowhere to be seen. They had begun a precipitate retreat, leaving all their provisions, artillery, ammunition, and baggage behind them. Their great campaign was over, ending in disastrous defeat. They endeavoured to make a stand at Sorel, being slightly reinforced, but the English troops which pressed on under Carleton and Burgoyne, the commander of the fresh arrivals, forced them to continue their flight. They were obliged to abandon their conquest at Montreal, Chambly, St. Johns, and Isle-aux-Noix, and did not deem themselves safe, till they reached the head of Lake Champlain. Then they paused and rallied, forming a strong army under Gates, and one year later, wreaked a terrible revenge upon this same Burgoyne, who had superseded Carleton, by capturing his whole army at Saratoga, thus gaining the first real step towards securing the independence of the Colonies. Arnold fought like a hero at that battle, giving proof of qualities which must have insured his success at Quebec if the fates had not been against him.