In 1851, the United States and the British Empire have stumbled into a war. The veterans of the US Army brushed aside the untried Canadians and advanced towards the St. Lawrence. Their advance was stopped only by the grim earthworks defending Montreal. Casualties have been high on both sides. A peace conference offered hope but it was wrecked by mutual suspicion. The harsh winter has kept the US Army from delivering a knockout blow. But everyone fears they will attack as soon as spring returns. This is a vicious war of raid and counter-raid. The frontier is a long one and the enemy could attack anywhere. The British are desperate enough to recruit Blacks, refugees who escaped north along the Underground Railroad. But these men are untrained and uncertain of themselves. They ask themselves whether they can stand against the seasoned professionals of the US Army. The men and women of Montreal can hear the enemy cannons but can only guess how the battle is going. This is a new sort of war where telegraph operators, men and women, know more about the battle than the generals. Grace is an Abenaki Indian, sent to a convent school in Quebec by ambitious parents. She ran away, hoping to find employment in the big city. She trained as a telegraphist, but was then given a more challenging task - preparing punched cards for the Analytical Engine. The airships of the Royal Mail Service are slow and fragile. They need reliable weather forecasts if they are to operate safely. Everyone expects the men operating the Analytical Engine to get it right every time. The industrial revolution has given Britain superior technology, but the government is reluctant to spend money on this war. Ships of the Royal Navy, operating from their impregnable base in Bermuda, are blockading US ports. They too depend upon weather forecasts. The US Army of Maine is led by the famous General, Winfield Scott, clever and popular. The British have the equally famous Colonel Lord Cardigan. He thinks that his aristocratic breeding is all that he needs to lead troops. Martin Wycombe made his way north from Alabama, hoping to gain freedom and self-respect. He expected to meet a heroic death in his first battle. Instead, he survived a series of squalid skirmishes. He has begun to ask what he is fighting for. The answer, when he found it, surprised him.