Lieutenant Colonel Kirby Yorke commands a remote cavalry outpost tasked with defending settlers from Apache raids. He is dedicated to his duty, but his personal life becomes complicated when his estranged son, Jeff, enlists in the army and is assigned to his unit. Tension arises as Yorke struggles to treat Jeff as any other soldier, masking his fatherly concern with stern discipline. Additionally, Yorke's former wife, Kathleen, arrives at the fort to take their son home, leading to further emotional strain.

As the Apaches launch relentless attacks, Yorke faces immense pressure to secure the area while managing complex family dynamics. Kathleen's presence rekindles unresolved feelings and confrontations about their past decisions and sacrifices. Yorke must navigate the dual responsibilities of commanding his troops and addressing his faltering family relationships amidst the impending threat.