Thomas Mower McDougall subsequently he was appointed Captain, 15 Dec 1875. In 1876 Captain McDougall commanded Company B and accompanied the 7th Cavalry Regiment, under command of Lt. Col. George A. Custer in its fateful departure from Fort Abraham Lincoln to participate in what became known as the Great Sioux War of 1876, which culminated in the Battle of the Little Bighorn, also known as Custer's Last Stand which occurred on June 25–26, 1876. On May 17, 1876, the 7th Cavalry left their base at Fort Abraham Lincoln near present day Mandan, North Dakota to join in a campaign against the Sioux Indians.
The Great Sioux Massacre 7th Cavalry and a promotion to brevet colonel. Captain Benton refuses and considers resigning his commission out of loyalty to his commander. Major Reno's daughter browbeats her father, who says he will not accept command of the regiment, gives his blessing to Caroline and Benton's marriage and gives up his drinking. In Washington Senator James G. Blaine visits the humbled Custer and tempts him with an offer to be the party's candidate for President of the United States. The Senator informs Custer this can be accomplished through obtaining a reputation through his military exploits in a war with the Indians.