A threatened Indian uprising sends the 13th Cavalry into camp. While scouting through the country a small party of soldiers drive their horses into a pool, thereby unwittingly profaning a sacred Indian spring. This incident takes place while the beautiful Indian girl Summer Morn is close to the spring. Calling her father, a strong protest is made against the sacrilege by the pale-faced soldiers. Lieutenant Bob, in charge of the scouting party, falls in love at first sight with the beautiful Indian girl. Pressing his suit, he finally gains the consent of her father to their marriage. The regiment, returning to headquarters, Bob's Indian wife is ostracized by the woman of the post. Recognizing the unfortunate position Bob is placed in, Summer Morn, although dearly loving her husband, steals away to her own people. Big Bear, her father, hides her and leads Bob to think that she is dead. Two years later Bob woos and wins Ruth. A camping honeymoon trip brings them into the Indian country. Accidentally meeting Summer Morn, Bob's old love instantly returns. The Indian girl, however, sends him away, and to make her sacrifice complete, throws herself into the sacred spring.