After finding a vital pass through the Canadian Rockies for the building of the Canadian Pacific Railway, Tom Andrews tells his boss Cornelius Van Horne that he is resigning to marry the girl he loves, Cecille Gautier. From Cecille, Tom learns that fur trader Dirk Rourke fears the coming of the railroad because it threatens his hold on the Indians and other trappers. Tom and Rorke have a bitter fight over Cecille, and Tom asks her to wait for him, as he has to go back and finish his job with the railroad. Aided by Dynamite Dawson, Tom finds evidence of Rourke`s work against the railroad construction and almost loses his life when Rourke fires into some crates of dynamite Tom is unloading. The construction camp`s doctor, Edith Cabot, gives her own blood in a transfusion to save Tom`s life. Cecille, realizing that her father is working with Rourke against the railroad,rides off to warn Tom.