In 1759, Langdon Towne, son of a ropemaker and ship rigger, returns to Portsmouth, New Hampshire, after his expulsion from Harvard University.

In need of Langdon's map-making skills, Rogers recruits the two men for his latest expedition to destroy the hostile Abenakis tribe and their town of St. Francis, far to the north.

Rogers's force rows north in whale boats on Lake Champlain by night, evading French patrols, but several soldiers are injured in a confrontation with Mohawk scouts.

Rogers sends not only the wounded back to Crown Point, but also the disloyal Mohawks provided by Sir William Johnson and a number of men who disobeyed orders.

Informed by Stockbridge Indian scouts that the French have captured their boats and extra supplies, Rogers revises his plan and sends an injured officer back to Fort Crown Point requesting the British send supplies to old Fort Wentworth, to be met by the returning rangers.

Encountering signs of French activity, Rogers prefers to press on a hundred miles to Fort Wentworth, but the men vote to split up into four parties to hunt for food.

Persevering through harsh conditions, Rogers and the remaining fifty men finally reach the fort, only to find it unoccupied and in disrepair, and the British relief column has not arrived.

The title is something of a misnomer, since this film is a truncated version of the original story, and only at the end do we find that Rogers and his men are about to go on a search for the Northwest Passage.

[2] The picture was originally slated for an even more lavish budget in an earlier incarnation and was to star Tracy and Wallace Beery but management difficulties between Irving Thalberg and Louis B. Mayer resulted in production being shelved at that time.

[4] Author Kenneth Roberts served as a co-writer on a second draft of a proposed script for the movie, one that covered the entire novel, not just the first book of it.

Director King Vidor then attempted to make a sequel to the film in which Rogers' Rangers find the Northwest Passage, although Roberts refused to cooperate with the project.

Clive Denton, in his 1976 book The Hollywood Professionals: Volume 5, made these observations on the subject: Vidor’s Northwest Passage “sits more than a trifle uneasily that [Spencer] Tracy and his submissive band attack and burn a sleeping Indian village.