On December 2, Arnold and Montgomery met on the outskirts of Quebec and demanded the surrender of the city. Governor Sir Guy Carleton rejected their demand, and on December 9 the Patriots commenced a bombardment of Quebec, which was met by a counterbattery by the British defenders that disabled several of the Patriots' guns. At approximately 4 a.m. on December 31, the Patriot forces advanced on the city under the cover of a blizzard. The British defenders were ready, however, and when Montgomery's forces came within 50 yards of the fortified city they opened fire with a barrage of artillery and musket fire. Montgomery was killed in the first assault, and, after several more attempts at penetrating Quebec's defenses, his men were forced into retreat.
Meanwhile, Arnold's division suffered a similar fate during their attack of the northern wall of the city. A two-gun battery opened fire on the advancing Americans, killing a number of Americans and wounding Benedict Arnold in the leg. Patriot Daniel Morgan assumed command, made progress against the defenders, but halted at the second wall of fortifications to wait for reinforcements. By the time the rest of Arnold's army finally arrived, the British had reorganized and the attack was called off. Of the 900 Americans who participated in the siege, 60 were killed and wounded and more than 400 were captured.
The remaining Patriot forces then retreated from the invasion of Canada. As the Americans crossed the St. Lawrence River to safety, Benedict Arnold remained in Canadian territory until the last of his soldiers had escaped. With the pursuing British forces almost in firing range, Arnold checked one last time to make sure all his men had escaped. He then shot his horse and fled down the St. Lawrence in a canoe.
Less than five years later, Benedict Arnold, as commander of West Point, famously became a traitor when he agreed to surrender the important Hudson River fort to the British for a bribe of $20,000. The plot was uncovered after British spy John André was captured with incriminating papers, forcing Arnold to flee to British protection and join in their fight against the country that he once so valiantly served.