One of Tex's closest friends, Colonel Jim Brandon, victim of a dark machination, is expelled from the Redcoat corps, demoted and sentenced to forced labor, confined to a fort on the shore of Athabasca Lake. After being informed of the incredible news by Gros-Jean, Night Eagle immediately leaves with his pards for Canada. The objective, obviously, is to prove Jim's innocence, discovering who is pulling the strings of that shady intrigue... But, first of all, Tex wants to free the brave officer of the North West Mounted Police from the labor camp in which he has been locked up... After a series of ambushes on Athabasca Lake, set by the shady Joe Larkin and all cleverly foiled, Tex and his pards, together with Gros-Jean and Marc Larouche, a river pirate who joined the group, arrive in the region of the penitentiary where Jim Brandon is locked up. But Jim is not one to sit idle and, feeling his life is in danger, he too is planning a way to escape from captivity... Tex and his pards manage to help Jim Brandon escape from the penitentiary where he was locked up, but now they have to prove his innocence and exonerate him from the infamous accusations that led to his unjust conviction. To do this, they travel to Ottawa. Meanwhile, in the Canadian capital, Senator Sidney and Major Fielding, at the head of a plot that Brandon was about to foil, study a plan to eliminate our heroes Nothing can stop the journey that Tex and his pards have undertaken to redeem Jim Brandon! With the complicity of the friends of the pirate Larouche, our men, changing boats to try to cover their tracks and escape the dense network of controls of the River Police, set course for Ottawa. Will the conspirators who gave Brandon the unjust sentence succeed in making the evidence of the conspiracy disappear before Tex arrives in the Canadian capital?
