The Last Frontier (1955)

Jed Cooper (Victor Mature), a trapper, enlists as an army fort scout, and shortly after meets and falls for Corinna Marston (Anne Bancroft), the wife of a nearby fort's commander. Jed comes across her husband, Col. Marston (Robert Preston), after he's suffered an attack at the hands of Native Americans. Col. Marston forces the captain of Jed's fort, Glenn Riordan (Guy Madison), to send out Jed and the troops to fight his attackers, despite their lack of battle experience.