Though Fort Randall is an isolated outpost in 1876, Miriam Longstreet finds life there far more complicated than she expected when she reluctantly returned from boarding school. Harriet, her haughty mother, is a laudanum addict, her free-spirited sister runs wild, and her father seems too occupied with his duties as commanding officer to notice. Miriam soon rebels at Harriet's insistence that she abide by the narrow rules of army social structure.