[3] Filmink called it "one of Errol's lesser war films and was far closer to the silliness of Desperate Journey than the more serious Edge of Darkness.

"[4] After a German U-boat drops off Nazi saboteurs, RCMP Corporal Wagner (Flynn) captures the leader, Colonel Hugo von Keller (Helmut Dantine), the only survivor after an avalanche wipes out the rest of the group.

His fiancée Laura McBain (Julie Bishop) is held as a hostage to ensure his loyalty but Wagner, acting as a double agent, manages to send a message to police headquarters to alert them of the Nazi saboteurs' plans.

Fellow Mountie Jim Austin (John Ridgely) follows their trail, but is spotted and killed, along with Willis and a native Canadian porter, before the group reaches a mine shaft where bomber components have been secreted before the war.

The bomber is assembled and takes off for its mission: to bomb the main waterway between the United States and Canada to disrupt transatlantic shipping of war materials.

[12] Warner Bros was aware that their star had recently been embroiled in a real-life scandal, with his acquittal in a rape trial only serving to increase the box-office "draw" of the 1943 feature.

Flynn is cast as the faithful lover and invariably brought down the house in 1943, after assuring his fiancée, Laura that she's the only woman he's ever loved, he turns away and quips, "What am I saying?

[13] Interiors and exteriors shot at the Burbank studios alternated with location shooting at Sun Valley, Idaho to replicate the Canadian north.