Defence Scheme No. 1 was created on April 12, 1921 and details a surprise counterattack on the northern U.S. as soon as possible after evidence was received of an American invasion of Canada.
According to the plan, Canadian troops stationed in Pacific Command in Western Canada would immediately be sent to seize Seattle, Washington; Canadian Forces stationed in Prairie Command in Western Canada would be sent to attack Great Falls, Montana and then move to Minneapolis, Minnesota; and Canadian Forces stationed in Quebec Command would be sent to seize Albany, New York in a surprise counterattack while Canadian Forces in Maritime Command[clarification needed] would counterattack into Maine. Meanwhile, according to the plan, the Canadian Forces Great Lakes Command in Ontario was assumed to be fighting on the defensive against the main attack from the Armed Forces of the USA; if Canadian forces were successful in defending in the Great Lakes area, they were encouraged to launch counterattacks in the area of the Niagara River and the St. Clair River.
When resistance stiffened, the Canadians would retreat to their own borders, destroying bridges and railways to hinder American pursuit. The purpose of the invasion would be to allow time for Canada to prepare its war effort and to receive aid from Britain, or to limit the American invasion before the US government opted to discontinue the incursions. Defence Scheme No. 1 has a counterpart in the American War Plan Red, a plan to invade Canada drafted in 1930.
This part is hilarious:
Lt. Colonel Brown himself did reconnaissance for the plan, along with other lieutenant-colonels, all in plainclothes. These missions took place from 1921 and 1926. As historian Pierre Berton noted in his book Marching as to War, these investigations had "a zany flavour about it, reminiscent of the silent comedies of the day." To illustrate this, Berton quoted from Brown's reports, in which Brown recorded, among other things, that in Burlington, Vermont the people were "affable" and thus unusual for Americans; that Americans drink significantly less alcohol than Canadians (this was during Prohibition), and that upon pointing out that to Americans, one responded "My God! I'd go for a glass of beer. I'm going to 'Canady' to get some more"; that the people of Vermont would be serious soldiers only "if aroused"; and that many Americans might be sympathetic with the British cause.
But yeah.. these plans are dragged out of the closet whenever somebody wants to drum up more hatred of America. One need only browse down to the comments of the OP article to see the effect.