On July 8, 1758, James Abercromby attacked Fort Carillon on Lake Champlain, but was repelled with heavy losses. In August, Montgomery and the 17th foot sailed to Boston, marched to join with Abercromby's forces in Albany and then moved to Lake George. On November 9, Abercromby was recalled; Amherst replaced him as commander-in-chief. The British high command, for the 1759 campaign, developed a plan for a three-pronged attack into Canada, in which forces including the 17th foot would assault Fort Carillon and also capture Fort St. Frédéric, near Crown Point, New York. Under Amherst's command, Montgomery and the 17th Foot participated in the capture of Fort Carillon. While the army was gathering prior to the battle, Montgomery's company was on guard duty; he ordered his men to remain vigilant for French and Indian ambush parties. On May 9 his suspicions proved correct when 12 men from the 17th were attacked. Montgomery and the 17th met stiff resistance at first. Montgomery ordered that his men were not to fire at night, fearing they would shoot their comrades. On July 21, the army began its movement toward Fort Carillon; by the 26th they were in position outside the fort's walls, from which the French had already withdrawn most of their forces to Fort St. Frédéric. That night, after some exchange of cannon fire during the day, the French blew up Carillon's powder magazine, and Fort St. Frédéric the next day, and withdrew to the far end of Lake Champlain.