During the Mexican-American War (1846 – 1848), Second Lieutenant Boyd fights in the United States Army (Boyd is obviously a former officer in the Army of the Republic of Texas, that merged with the US Army in 1846 - he still wears the Texas Army rank insignia of second lieutenant: one five pointed star on each shoulder strap). But in battle his courage fails him, and, to avoid being killed, he plays dead—while his unit is massacred. He is transported along with the other dead (with his commanding officer's blood dripping into his mouth) back to the Mexican headquarters. However, in a moment of sudden bravery, he captures the Mexican command. For his heroism Boyd is promoted to Captain, but when his commanding officer learns of the cowardice by which his victory was achieved, he exiles Boyd to the remote Fort Spencer in the Sierra Nevada mountain range.