Two career Marines, one officer, Dan Tucker, and one enlisted man, Owen Callahan, cross paths throughout their years in the Marine Corps. Early in their careers, Lieutenant Tucker gets Sergeant Callahan and his family transferred from a tough assignment in the face of strong pressure from Dan's senior officers. Owen and his wife, who has undergone a difficult childbirth, are forever grateful. Later the two men serve together in combat in an ugly war in the middle East. Gunnery Sergeant Callahan is with Major Tucker when they are caught in a firefight at night. The major is badly wounded and Gunny Callahan helps get him to safety. Later they are both in senior positions when Dan is a regimental commander and Owen is his sergeant major. Their long professional friendship becomes strained when Owen's daughter Katy, the Callahans' only child, becomes romantically attached to the colonel, an older man who was divorced and is years older than she is. Now the only thing that can come between the two Marine comrades is their strong feelings for the same young woman: the sergeant's daughter.