One brilliant afternoon, as she lay on the broad, cane-bottomed bedstead with its overhanging canopy of filmy netting, she drowsily heard the corporal posting the new sentry in the marbled corridor below, and then marching the relief to the rear gate opening to the beach. Nita was already up and moving about in her room. Margaret heard the rustle of her skirts and the light patter of her tiny feet as she sped over the hardwood floor of the main _salon_. She heard her throwing back the sliding shutters that kept out the glare of the sun in the morning hours, and knew that she was gazing out over the tree-dotted lawn toward the gate where the guard lounged through the warm afternoon. All of a sudden, quick and stirring, a bugle sounded over on the Calle Nueva, where the North Dakotas had a strong detachment. The call was repeated, and, army woman though she was, she did not recognize it. She could not remember ever having heard it before. Then up the street, from the Engineer barrack, there came thrilling echo, and there was a sound of movement and excitement along the dusty thoroughfare. She heard Nita calling her name, and then the child's quick, nervous step along the hallway toward the stairs. Then came a sudden stop, a gasping, wailing cry, and, springing from her bed and to the door, Margaret found her sister cowering before a tall, slender man in the rough dress and field equipment of a private soldier. With a little packet--letters, apparently--held forth in one hand, while the other grasped her wrist, Rollin Latrobe stood sternly gazing at the girl shrinking at his feet. The tableau was over in another second. Springing up the broad marble stairs came Billy Gray, the corporal of the guard at his heels, and Latrobe saw his danger in a flash. Throwing little Gray aside as he would a terrier, the young athlete whirled on the stalwart regular. There was the sound of a crashing blow, followed by a heavy fall. The corporal went rolling down the steps with Latrobe bounding over the tumbling form, and the next instant he had vaulted over the ledge of the open window on the lower floor, and vanished through the gateway to the beach. And now all along the Calle Real the bugles were sounding "To Arms!" CHAPTER XVI.