An orderly was holding horses outside a dirty little estaminet, and, riding his machine on the cobbled sidewalk, a motor dispatch-rider threaded his way with marvellous skill among the little groups of villagers and fatigue parties.
Where a lane crossed the street at right angles he saw the white line of a trench close to the backs of the houses, and walked towards it.
At the corner of the trench a Red Cross nurse was in the act of posting a letter in the field collection box. There were nurses from the waiting ambulance train among the crowd in the street.
After a long gaze over the country beyond the trench he returned to retrace his steps, when something in the attitude of the nurse at the pillar-box attracted his attention. Her back was towards him, and she was peering round the angle in a furtive kind of way.
He stood still, and then he noticed that the door of the collecting box was open, and that while she peered along the deserted trench she was gathering the letters and dropping them into a receptacle beneath her white apron.
"I didn't know they had women letter carriers out here," thought Dennis; "possibly they take them down on the hospital train for quickness' sake—and yet——"
An indefinable suspicion followed on the heels of his surmise as the girl turned her head, and in an instant he recognised the red hair and dark eyes of the waitress in the London restaurant.
The rumble of the motor lorries at the cross-roads deadened the noise of his approach as he came softly up behind her, and then his suspicions were confirmed beyond any possibility of doubt.
"Got you at last, Frau von Dussel!" he exclaimed, seizing her arm; and with a low cry she dropped a bunch of letters on to the ground, thrust her hand into the breast of her apron, and drew out a Browning pistol.
But he was too quick for her, and his fingers closed like a vice on her wrist.