Roger Lamb, a young Dublin scapegrace, joins the 9th Regiment of Foot and quickly rises to the rank of sergeant. He falls for a local girl, Kate, but she marries another soldier, "Gentleman" Richard Harlowe, who is thereafter an enemy of Lamb's. His regiment is posted to America soon after the outbreak of hostilities with the colonists. There follows a survey of the causes of the American war. Landing at Quebec, Lamb and his regiment move upcountry, and are soon engaging the American expeditionary force in Canada. He witnesses the naval engagements on Lake Champlain, then is chosen, with one comrade, to accompany the Mohawk chief Thayendanegea on a three-month hunting expedition. He learns much about life among the Six Nations, and encounters Kate Harlowe, who has left her husband and joined the Ottawa tribe. Lamb and Kate are married in Indian fashion, but when Lamb returns to Montreal Kate remains with the Ottawa. Rejoining his regiment he takes part in the siege of Ticonderoga. Some time later, near Fort Edward, Lamb is charged with a lone mission to return through the forest to Ticonderoga, there to organize the transport of military stores. This he does, but on the way again chances on Kate, who is giving birth to their child. Kate leaves the baby to be looked after by a Quaker settler. Lamb takes part in a battle at Bemis Heights, in the course of which he learns by another accidental encounter that "Gentleman" Harlowe had long ago married and deserted another wife. Hostilities at Saratoga end with the surrender of Lamb's regiment. They are marched to Cambridge, Mass., in expectation of being shipped back to Britain.