A military ball is in progress at the post and all the officers and young men of the regiment are tripping the light fantastic. Carlton Langdon, a surgeon of the garrison, is disliked by most of the fellows in his company for surly manner and peculiar nervous irritability. For a time no one suspected the real cause of his bearing, but secrets, such as he held, are sooner or later discovered, and so it was with no surprise that reports of him being addicted to the use of morphine gained credence. He was in spite of his failing, however, a splendid surgeon and for that reason more than any other he was tolerated and his eccentricities overlooked. Now the Colonel of the post had a beautiful daughter, Isabel, for whom Langdon entertained a feeling closely allied to worship. The thought of possessing her for his wife grew upon him day by day until it became the one great absorbing interest of his life. For her, he made a desperate effort to relinquish the drug that seemed to have him as in a grip of steel and for a long while almost succeeded. But repeated failures in his efforts to obtain one ray of hope from the fair Isabel drove him back to the fatal vice that seemed to saddle itself upon him with redoubled fury. In the opening scene of the picture we see him, nerve-racked, with staring eyes and trembling hands. He makes one last appeal to the object of his adoration and receives a rebuff that completely stuns him and leaves him limp, and broken in heart and spirit. Isabel tells him that it is useless for him to plead his cause further. That she has just given her heart and hand to Earl Holden, Troop D’s dashing first lieutenant. With a toss of her pretty head she trips away to join the others at the banquet table. It is Christmas time and the spirit of revelry and joy pervades the entire post. Everyone seems happy; everyone but Langdon, whose passion is just then eating at his heart. With a bitter curse for his hated rival, he staggers out into the night to cool his fevered brow and try to regain his composure. A horseman is seen in the distance making his way laboriously toward the gates. It’s a carrier from headquarters. Springing from his mount, he makes his way into the stockade and from there to the big mess room where the banquet is in progress. He bears an important message to the Colonel. The Sioux are again on the warpath, committing many depredations and terrifying the settlers for miles around. “Send out a squad to investigate conditions,” says the General in his message. The Colonel knows it will require men of nerve and unusual daring, so the first man he thinks of to head the expedition is the handsome Lieutenant of Troop D, young Holden. Orders are quickly given and acted upon, and while the dance is still in full sway, a little squad of cavalry files out through the heavy gates and is soon lost to view. Watching them out of sight, Langdon laughs in mirthless tones to think of the danger that lurks on every hand beyond those forbidding hills. “He will never come back alive. He will never return to her alive,” the maddened surgeon repeats, over and over again. And his prophecy nearly comes true. For the sun has scarcely kissed the hilltops with his shafts of fiery red, when the little squad of fighting men ride direct into an Indian ambuscade. It is a fight to the death; no quarter is asked or given. Finally by sheer bravery and superior marksmanship the boys in blue scatter their treacherous foe and return to look after their own dead and wounded. The Lieutenant is found with an ugly hole in his side and almost dead from the loss of blood. Tenderly his men lift him on to a hastily improvised drag and urging their jaded horses to their utmost strength, the long, desperate return journey is begun. Toward evening the sentries at the post sight the little cavalcade coming through the snow and at once the alarm is given, so that when the worn and half dead expedition reaches the outer gates, every preparation has been made for their comfort and for the care of the wounded. Bearing up with remarkable tenacity, Holden wins the fight against death and in a few days is on the road to recovery, much to the joy of his sweetheart and to the bitter disappointment of his rival, the surgeon. In his crazed mind Langdon finally conceives and nearly carries into execution a most diabolical plot. Mixing a deadly concoction, he attempts to poison the Lieutenant, but is frustrated by the watchful eye of Old Pete, the negro cook, who happens upon the surgeon as he is mixing the fatal potion. This last net of madness ends Langdon’s career at the post, for he is placed under arrest, but afterward escapes and perishes in the cold, having wandered for miles aimlessly about, until overcome by fatigue he lies down and the snow falling quietly covers him in its white shroud. Young Holden rapidly recovers and soon resumes his duties and the near future holds for him a most pleasing prospect in the shape of Miss Isabel Walton, the colonel’s charming daughter, who has promised to become Mrs. Earl Holden on her next birthday.